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SUSE Linux Enterprise Server for SAP Applications 12 SP4

SAP HANA System Replication Scale-Up - Cost Optimized Scenario

SUSE® Linux Enterprise Server for SAP Applications is optimized in various ways for SAP* applications. This guide provides detailed information about installing and customizing SUSE Linux Enterprise Server for SAP Applications for SAP HANA Scale-Up system replication automation in the cost optimized scenario. It is based on SUSE Linux Enterprise Server for SAP Applications 12 SP4. The concept however can also be used with SUSE Linux Enterprise Server for SAP Applications 12 SP5 or newer.

Disclaimer: This document is part of the SUSE Best Practices series. All documents published in this series were contributed voluntarily by SUSE employees and by third parties. If not stated otherwise inside the document, the articles are intended only to be one example of how a particular action could be taken. Also, SUSE cannot verify either that the actions described in the articles do what they claim to do or that they do not have unintended consequences. All information found in this document has been compiled with utmost attention to detail. However, this does not guarantee complete accuracy. Therefore, we need to specifically state that neither SUSE LLC, its affiliates, the authors, nor the translators may be held liable for possible errors or the consequences thereof.

Author: Fabian Herschel, Distinguished Architect SAP, SUSE
Author: Bernd Schubert, SAP Solution Architect, SUSE
Author: Lars Pinne, System Engineer, SUSE
Publication Date: 2020-09-28

1 About This Guide

1.1 Introduction

SUSE® Linux Enterprise Server for SAP Applications is optimized in various ways for SAP* applications. This guide provides detailed information about installing and customizing SUSE Linux Enterprise Server for SAP Applications for SAP HANA system replication in the cost optimized scenario.

SAPHanaSR ScaleUP costOpt2
Figure 1: cost optimized scenario described in this best practice

For an overview of supported scenarios, see Section 1.1.3, “Scale-Up Scenarios and Resource Agents”.

SAP HANA is the only database platform for prominent SAP platforms like SAP S/4HANA. SAP NetWeaver can also use SAP HANA as database back-end. As SAP HANA is only available on the Linux operating system, this triggers lots of Unix-to-Linux and Windows-to-Linux migrations.

SUSE is accommodating this development by offering SUSE Linux Enterprise Server for SAP Applications, the recommended and supported operating system for SAP HANA. In close collaboration with SAP, cloud service and hardware partners, SUSE provides two resource agents for customers to ensure the high availability of SAP HANA system replications.

1.1.1 Abstract

This guide describes planning, setup, and basic testing of SUSE Linux Enterprise Server for SAP Applications based on the high availability solution scenario "SAP HANA Scale-Up System Replication Cost Optimized".

From the application perspective the following variants are covered:

  • plain system replication

  • multi-tenant database containers

From the infrastructure perspective the following variants are covered:

  • 2-node cluster with disk-based SBD

  • 3-node cluster with diskless SBD

  • on-premise deployment on physical and virtual machines

  • public cloud deployment (usually needs additional documentation focusing on the cloud specific implementation details)

See Section 2, “Supported Scenarios and Prerequisites” for details.

1.1.2 Scale-Up Versus Scale-Out

The first set of scenarios includes the architecture and development of scale-up solutions.

hana sr in cluster
Figure 2: SAP HANA System Replication Scale-Up in the Cluster

For these scenarios SUSE has developed the scale-up resource agent package SAPHanaSR. System replication helps to replicate the database data from one computer to another to compensate for database failures (single-box replication).

The second set of scenarios includes the architecture and development of scale-out solutions (multi-box replication). For these scenarios SUSE has developed the scale-out resource agent package SAPHanaSR-ScaleOut.

SAPHanaSR ScaleOut Cluster
Figure 3: SAP HANA System Replication Scale-Out in the Cluster

With this mode of operation, internal SAP HANA high availability (HA) mechanisms and the resource agent must work together or be coordinated with each other. SAP HANA system replication automation for scale-out is described in a separate document available on our documentation Web page at https://documentation.suse.com/sbp/all/. The document for scale-out is named "SAP HANA System Replication Scale-Out - Performance Optimized Scenario".

1.1.3 Scale-Up Scenarios and Resource Agents

SUSE has implemented the scale-up scenario with the SAPHana resource agent (RA), which performs the actual check of the SAP HANA database instances. This RA is configured as a multi-state resource. In the scale-up scenario, the promoted RA instance assumes responsibility for the SAP HANA databases running in primary mode. The non-promoted RA instance is responsible for instances that are operated in synchronous (secondary) status.

To make configuring the cluster as simple as possible, SUSE has developed the SAPHanaTopology resource agent. This RA runs on all nodes of a SUSE Linux Enterprise Server for SAP Applications cluster and gathers information about the statuses and configurations of SAP HANA system replications. It is designed as a normal (stateless) clone.

SAP HANA System replication for Scale-Up is supported in the following scenarios or use cases:

  • Performance optimized (A ⇒ B). This scenario and setup is described in another document available from the documentation Web page (https://documentation.suse.com/sbp/all/). The document for performance optimized is named "SAP HANA System Replication Scale-Up - Performance Optimized Scenario".

    SAPHanaSR ScaleUP perfOpt
    Figure 4: SAP HANA System Replication Scale-Up in the Cluster - performance optimized

    In the performance optimized scenario an SAP HANA RDBMS site A is synchronizing with an SAP HANA RDBMS site B on a second node. As the SAP HANA RDBMS on the second node is configured to pre-load the tables, the takeover time is typically very short.

    One big advance of the performance optimized scenario of SAP HANA is the possibility to allow read access on the secondary database site. To support this read enabled scenario, a second virtual IP address is added to the cluster and bound to the secondary role of the system replication.

  • Cost optimized (A ⇒ B, Q). This scenario and setup is described in this document.

    SAPHanaSR ScaleUP costOpt2
    Figure 5: SAP HANA System Replication Scale-Up in the Cluster - cost optimized

    In the cost optimized scenario the second node is also used for a non-replicated SAP HANA RDBMS system (like QAS or TST). Whenever a takeover is needed, the non-replicated system must be stopped first. As the productive secondary system on this node must be limited in using system resources, the table preload must be switched off. A possible takeover needs longer than in the performance optimized use case.

    In the cost optimized scenario the secondary needs to be running in a reduced memory consumption configuration. This is why read enabled must not be used in this scenario.

    As already explained, the secondary SAP HANA database must run with memory resource restrictions. The HA/DR provider needs to remove these memory restrictions when a takeover occurs. This is why multi SID (also MCOS) must not be used in this scenario.

  • Multi Tier (A ⇒ B → C) and Multi Target (B ⇐ A ⇒ C).

    SAPHanaSR ScaleUP Chain
    Figure 6: SAP HANA System Replication Scale-Up in the Cluster - performance optimized chain

    A Multi Tier system replication has an additional target. In the past this third side must have been connected to the secondary (chain topology). With current SAP HANA versions, the multiple target topology is allowed by SAP.

    SAPHanaSR ScaleUP MultiTarget
    Figure 7: SAP HANA System Replication Scale-Up in the Cluster - performance optimized multi target

    Multi tier and multi target systems are implemented as described in the document for the performance optimized scenario named "SAP HANA System Replication Scale-Up - Performance Optimized Scenario". Multi tier and multi target systems are only supported in the performance optimized scenario and not with the cost optimized scenario. They are mentioned here to give an overview of our entire portfolio of solutions.

In the multi tier and multi target scenario only the first replication pair (A and B) is handled by the cluster itself.

  • Multi-tenancy or MDC.

    Multi-tenancy is supported for all above scenarios and use cases. This scenario is supported since SAP HANA SPS09. The setup and configuration from a cluster point of view is the same for multi-tenancy and single container. Thus you can use the above documents for both kinds of scenarios.

1.1.4 The Concept of the Cost Optimized Scenario

SAP allows to run a non-replicated instance of SAP HANA on the system replication site on the secondary site. Such a non-replicated database could be development (DEV), test (TST), or quality assurance system (QAS).

In case of a failure of the primary SAP HANA on the primary site the cluster first tries to restart the failed SAP HANA database locally on this node. If the restart is not possible or if the complete primary node crashed, the takeover process will be triggered.

In case of a takeover the secondary (replica) of this SAP HANA on node 2 is promoted after the shutdown of the non-replicated SAP HANA.

Alternatively you can configure a different resource handling procedure, but we recommend to try to restart SAP HANA locally first, as a takeover with non-preloaded tables can consume much time. Also, the needed graceful stop of the non-replicated system will take additional time. Thus, in many environments, the local restart will be faster.

To achieve an automation of this resource handling process, use the SAP HANA resource agents included in SAPHanaSR. System replication of the productive database is done using the resource agents SAPHana and SAPHanaTopology. The handling of the non-replicated database is implemented using the SAPInstance resource agent.

While SAPHana and SAPHanaTopology are driving the automation of the SAP HANA system replication, SAPInstance is used for the non-replicated SAP HANA database. In the past the architecture made use of SAPDatabase instead. The move to SAPInstance was needed to get rid of the error-prone user secure store keys setup procedure. Find more details in the blog article "SAP HANA Cost-optimized – An alternative Route is available" at https://suse.com/c/sap-hana-cost-optimized-an-alternative-route-is-available/.

The automated shutdown of the non-replicated SAP HANA database (e.g. QAS) is achieved by cluster rules. More precisely, it is an anti-colocation of SAP HANA promoted vs. SAP HANA non-replicated. This means if the primary SAP HANA system (like HA1) fails, the anti-colocation rules for the SAP HANA non-replicated system (like QAS) are triggered and the SAPInstance resource agent shuts down the non-replicated SAP HANA database.

The takeover to the secondary site takes up a lot of time, because the non-replicated database needs to be stopped gracefully prior to takeover the productive database. This extended takeover time is the main disadvantage of the cost optimized scenario. Thus the cost optimized scenario might be combined with persistent memory to benefit from SAP HANA’s persistent memory features.

Note
Note

If you want to achieve a very fast takeover, the performance optimized scenario is the better option.

In addition to the description of the concept in this best practice document, read the corresponding SAP documentation such as "Using Secondary Servers for Non-Productive systems". The section is available for exaample for SAP HANA 2.0 SPS05 at https://help.sap.com/viewer/6b94445c94ae495c83a19646e7c3fd56/2.0.05/en-US/5447545b91a04cf8a0d6133a026f2be5.html.

The cluster only allows a takeover to the secondary site if the SAP HANA system replication was in sync until the point when the service of the primary got lost. This ensures that the last commits processed on the primary site are already available at the secondary site.

SAP did improve the interfaces between SAP HANA and external software, such as cluster frameworks. These improvements also include the implementation of SAP HANA call outs in case of special events, such as status changes for services or system replication channels. These call outs are also called HA/DR providers. These interfaces can be used by implementing SAP HANA hooks written in python. SUSE has enhanced the SAPHanaSR package to include such SAP HANA hooks to optimize the cluster interface. Using the SAP HANA hooks described in this document allows to inform the cluster immediately if the SAP HANA system replication is broken. In addition to the SAP HANA hook status, the cluster continues to poll the system replication status on a regular basis.

You can set up the level of automation by setting the parameter AUTOMATED_REGISTER. If automated registration is activated, the cluster will automatically register a former failed primary to become the new secondary.

Important
Important

The solution is not designed to manually 'move' the primary or secondary instance using HAWK or any other cluster client commands. In Section 11, “Administration” of this document we describe how to 'migrate' the primary to the secondary site using SAP and cluster commands.

1.2 Ecosystem of the Document

1.2.1 Additional Documentation and Resources

Chapters in this manual contain links to additional documentation resources that are either available on the system or on the Internet.

For the latest documentation updates, see http://documentation.suse.com/.

Numerous whitepapers, best practices documents, setup guides, and other resources ar available from the SUSE Best Practices Web page under the categories 'SAP Applications on SUSE Linux Enterprise' at https://documentation.suse.com/sbp/all/.

SUSE also publishes blog articles about SAP and high availability. Join us by using the hashtag #TowardsZeroDowntime. Use the following link: https://www.suse.com/c/tag/TowardsZeroDowntime/.

1.2.2 Errata

To deliver urgent smaller fixes and important information in a timely manner, the Technical Information Document (TID) for this setup guide will be updated, maintained and published at a higher frequency:

In addition to this guide, check the SUSE SAP Best Practice Guide Errata for other solutions (https://www.suse.com/support/kb/doc/?id=7023713).

1.2.3 Feedback

Several feedback channels are available:

Bugs and Enhancement Requests

For services and support options available for your product, refer to http://www.suse.com/support/.

To report bugs for a product component, go to https://scc.suse.com/support/ requests, log in, and select Submit New SR (Service Request).

Mail

For feedback on the documentation of this product, you can send a mail to doc-team@suse.com. Make sure to include the document title, the product version and the publication date of the documentation. To report errors or suggest enhancements, provide a concise description of the problem and refer to the respective section number and page (or URL).

2 Supported Scenarios and Prerequisites

With the SAPHanaSR resource agent software package, we limit the support to Scale-Up (single-box to single-box) system replication with the following configurations and parameters:

  • Two-node clusters are standard. Three node clusters are fine if you install the resource agents also on that third node. But define in the cluster that SAP HANA resources must never run on that third node. In this case the third node is an additional decision maker in case of cluster separation.

  • The cluster must include a valid STONITH method.

    • Any STONITH mechanism supported for production use by SUSE Linux Enterprise High Availability Extension 12 (like SBD, IPMI) is supported with SAPHanaSR.

    • This guide is focusing on the SBD fencing method as this is hardware independent.

    • If you use disk-based SBD as the fencing mechanism, you need one or more shared drives. For productive environments, we recommend more than one SBD device. For details on disk-based SBD, read the product documentation for SUSE Linux Enterprise High Availability Extension and the manual pages sbd(8) and stonith_sbd(7).

    • For diskless SBD you need at least three cluster nodes. The diskless SBD mechanism has the benefit that you do not need a shared drive for fencing.

  • Both nodes are in the same network segment (layer 2). Similar methods provided by cloud environments such as overlay IP addresses and load balancer functionality are also fine. Follow the cloud specific guides to set up your SUSE Linux Enterprise Server for SAP Applications cluster.

  • Technical users and groups, such as <sid>adm are defined locally in the Linux system. If that is not possible, additional measures are needed to ensure reliable resolution of users, groups and permissions at any time. This might include caching.

  • Name resolution of the cluster nodes and the virtual IP address must be done locally on all cluster nodes. If that is not possible, additional measures are needed to ensure reliable resolution of hostnames at any time.

  • Time synchronization between the cluster nodes, such as NTP, is required.

  • Both SAP HANA instances of the system replication pair (primary and secondary) have the same SAP Identifier (SID) and instance number.

  • If the cluster nodes are installed in different data centers or data center areas, the environment must match the requirements of the SUSE Linux Enterprise High Availability Extension cluster product. Of particular concern are the network latency and recommended maximum distance between the nodes. Review our product documentation for SUSE Linux Enterprise High Availability Extension about those recommendations.

  • Automated registration of a failed primary after takeover prerequisites need to be defined.

    • As initial configuration for projects, we recommend to switch off the automated registration of a failed primary. The setup AUTOMATED_REGISTER="false" is set as default. In this case, you need to register a failed primary after a takeover manually. Use SAP tools like SAP HANA cockpit or hdbnsutil.

    • For optimal automation, we recommend to set AUTOMATED_REGISTER="true".

    • The cluster automates one single takeover in case of a failed primary. After that happened, the initial state has to be restored by the administrative procedure outlined in this guide.

  • Automated start of SAP HANA instances during system boot must be switched off.

  • Multi-tenancy (MDC) databases are supported.

    • Multi-tenancy databases can be used in combination with any other setup (performance based, cost optimized and multi-tier).

    • In MDC configurations the SAP HANA RDBMS is treated as a single system including all database containers. Therefore cluster takeover decisions are based on the complete RDBMS status independent of the status of individual database containers.

    • Tests on Multi-tenancy databases can force a different test procedure if you are using strong separation of the tenants. As an example, killing the complete SAP HANA instance using HDB kill does not work, because the tenants are running with different Linux user UIDs. <sid>adm is not allowed to terminate the processes of the other tenant users.

  • SUSE Linux Enterprise Server for SAP Applications versions:

    • You need at least SAPHanaSR version 0.154 and at least SUSE Linux Enterprise Server for SAP Applications 12 SP4.

    • Intel Optane DCPMM (aka PMEM) is supported since SUSE Linux Enterprise Server for SAP Applications 12 SP4 or newer.

  • SAP HANA versions:

    • SAP HANA 1.0 is supported since SPS09 (095) for all mentioned setups. SAP HANA 1.0 does not support the HA/DR provider hook method srConnectionChanegd() with multi-target aware parameters. These parameters are needed for the HA/DR hook in the package.

    • For SAP HANA 1.0 you need version SPS10 rev3, SPS11 or newer if you want to stop tenants during production and you want the cluster to be able to take over. Older SAP HANA versions are marking the system replication as failed if you stop a tenant.

    • SAP HANA 2.0 SPS04 or later provides the needed HA/DR provider hook method srConnectionChanegd() with multi-target aware parameters.

    • Particularly the SAP HANA system replication cost optimized scenario can benefit from SAP HANA’s persistent memory features. Local restart and take-over are affected by the time SAP HANA needs for shutdown and loading column store. SAP HANA 2.0 SPS04 and later support persistent memory.

Important
Important

Without a valid STONITH method, the complete cluster is unsupported and will not work properly.

If you need to implement a different scenario, we strongly recommend to define a Proof of Concept (PoC) with SUSE. This PoC will focus on testing the existing solution in your scenario. Most of the above mentioned limitations are set because careful testing is needed.

In addition to SAP HANA, you need to install the SAP Host Agent on your system.

For information on supported hardware and virtualization, refer to the SUSE release notes and hardware compatibility database: * https://www.suse.com/releasenotes/ * https://www.suse.com/yessearch/

Also, take a look at the SAP HANA product availability matrix, which can for example be found at https://support.sap.com/en/release-upgrade-maintenance.html#section_1969201630

Additional information for deploying the cost optimized scenario in particular public clouds is available either from the respective cloud provider or at SUSE: https://documentation.suse.com/sbp/all/

3 Scope of This Document

This document describes how to set up the cluster to control SAP HANA in System Replication scenarios. The document focuses on the steps to integrate an already installed and working SAP HANA with System Replication.

The described example setup builds an SAP HANA HA cluster in two data centers in Walldorf (WDF) and in Rot (ROT), installed on two SLES for SAP 12 SP4 systems. In addition, a non-replicated SAP HANA is installed and added to the cluster control.

SAPHanaSR ScaleUP costOpt2
Figure 8: Cluster with SAP HANA SR - cost optimized

You can either set up the cluster using the YaST wizard, doing it manually or using your own automation.

If you prefer to use the YaST wizard, you can use the shortcut yast sap_ha to start the module. The procedure to set up SAPHanaSR using YaST is described in the product documentation of SUSE Linux Enterprise Server for SAP Applications in section Setting Up an SAP HANA Cluster at https://documentation.suse.com/sles-sap/12-SP4/single-html/SLES4SAP-guide/#cha-s4s-cluster.

Yast SAP HA
Figure 9: Scenario Selection for SAP HANA in the YaST Module sap_ha

This guide focuses on the manual setup of the cluster to explain the details and to give you the possibility to create your own automation.

The seven main setup steps are:

SAPHanaSR ScaleOut Plan Phase0

4 Planning the Installation

SAPHanaSR ScaleOut Plan Phase1

Planning the installation is essential for a successful SAP HANA cluster setup.

Before you start, you need the following:

  • Software from SUSE: SUSE Linux Enterprise Server for SAP Applications installation media, a valid subscription, and access to update channels

  • Software from SAP: SAP HANA installation media

  • Physical or virtual systems including disks

  • Filled parameter sheet (see below Section 4.2, “Parameter Sheet”)

4.1 Minimum Lab Requirements and Prerequisites

Note
Note

The minimum lab requirements mentioned here are by no means SAP sizing information. These data are provided only to rebuild the described cluster in a lab for test purposes. The following minimum setup uses the half-size of RAM for the secondary SAP HANA database which has table preload inactive. Even for tests the requirements can increase, depending on your test scenario. For productive systems ask your hardware vendor or use the official SAP sizing tools and services. Refer to the SAP HANA TDI documentation for allowed storage configuration and file systems.

Requirements with 1 SAP system replication instance per site (1 : 1) - without a majority maker (2 node cluster):

  • 1 VM with 32GB RAM, 50 GB disk space for the system

  • 1 VM with 48GB RAM, 50 GB disk space for the system

  • 1 shared disk for SBD with 10 MB disk space

  • 2 data disks (one per site) with a capacity of each 96 GB for SAP HANA

  • 1 data disk (for the non-replicated database) with a capacity of 96 GB for SAP HANA

  • 1 additional IP address for takeover

  • 1 additional IP address for non-replicated database

  • 1 optional IP address for HAWK Administration GUI

Requirements with 1 SAP system replication instance per site (1 : 1) - with a majority maker (3 node cluster):

  • 1 VM with 32 GB RAM, 50 GB disk space for the system

  • 1 VM with 48 GB RAM, 50 GB disk space for the system

  • 1 VM with 2 GB RAM, 50 GB disk space for the system

  • 2 data disks (one per site) with a capacity of each 96 GB for SAP HANA

  • 1 data disk (for the non-replicated database) with a capacity of 96 GB for SAP HANA

  • 1 additional IP address for takeover

  • 1 additional IP address for non-replicated database

  • 1 optional IP address for HAWK Administration GUI

4.2 Parameter Sheet

Even if the setup of the cluster organizing two SAP HANA sites is quite simple, the installation should be planned properly. You should have all needed parameters like SID, IP addresses and much more in place. It is good practice to first fill out the parameter sheet and then begin with the installation.

Table 1: Parameter Sheet for Planning
ParameterValueRole

node 1

 

Cluster node name and IP address.

node 2

 

Cluster node name and IP address.

SID

 

SAP System Identifier of the replicated SAP HANA database

Instance Number

 

Number of the SAP HANA database. For system replication also Instance Number+1 is blocked.

SID non-replicated

 

SAP System Identifier of the non-replicated SAP HANA database

Instance Number

 

Number of the non-replicated SAP HANA database.

Network mask

  

vIP primary

 

Virtual IP address to be assigned to the primary SAP HANA site

vIP non-replicated

 

Virtual IP address to be assigned to the non-replicated SAP HANA system (optional)

Storage

 

Storage for HDB data and log files is connected “locally” (per node; not shared)

SBD

 

STONITH device (two for production) or diskless SBD

HAWK Port

7630

 

NTP Server

 

Address or name of your time server

Table 2: Parameter Sheet with Values used in this Document
ParameterValueRole

node 1

suse01, 192.168.1.11

Cluster node name and IP address.

node 2

suse02, 192.168.1.12

Cluster node name and IP address.

SID

HA1

SAP System Identifier of the replicated SAP HANA database

Instance Number

10

Number of the SAP HANA database. For system replication also Instance Number+1 is blocked.

SID non-replicated

QAS

SAP System Identifier of the non-replicated SAP HANA database

Instance Number

20

Number of the non-replicated SAP HANA database.

Network mask

255.255.255.0

 

vIP primary

192.168.1.20

 

vIP non-replicated

192.168.1.22

(optional)

Storage

 

Storage for HDB data and log files is connected “locally” (per node; not shared)

SBD

/dev/disk/by-id/SBDA

STONITH device (two for production) or diskless

HAWK Port

7630

 

NTP Server

pool pool.ntp.org

Address or name of your time server

5 Operating System Setup

SAPHanaSR ScaleOut Plan Phase2

This section contains information you should consider during the installation of the operating system.

For the scope of this document, first SUSE Linux Enterprise Server for SAP Applications is installed and configured. Then the SAP HANA database including the system replication is set up. Finally the automation with the cluster is set up and configured.

5.1 Installing SUSE Linux Enterprise Server for SAP Applications

Multiple installation guides already exist, for different purposes and with different reasons to set up the server in a certain way. Below it is outlined where this information can be found. In addition, you will find important details you should consider to get a well-working system in place.

5.1.1 Installing Base Operating System

Depending on your infrastructure and the hardware used, you need to adapt the installation. All supported installation methods and minimum requirement are described in the Deployment Guide for SUSE Linux Enterprise Server (https://documentation.suse.com/sles/12-SP4/html/SLES-all/book-sle-deployment.html). In case of automated installations you can find further information in the AutoYaST Guide (https://documentation.suse.com/sles/12-SP4/html/SLES-all/book-autoyast.html). The main installation guides for SUSE Linux Enterprise Server for SAP Applications that fit all requirements for SAP HANA are available from the SAP notes:

  • 1984787 SUSE LINUX Enterprise Server 12: Installation notes

  • 2205917 SAP HANA DB: Recommended OS settings for SLES 12 / SLES for SAP Applications 12.

5.1.2 Installing Additional Software

With SUSE Linux Enterprise Server for SAP Applications, SUSE delivers special resource agents for SAP HANA. With the pattern sap-hana, the resource agent for SAP HANA scale-up is installed. For the scale-out scenario you need a special resource agent. Follow the instructions below on each node if you have installed the systems based on SAP note 1984787. The pattern High Availability summarizes all tools recommended to be installed on all nodes, including the majority maker.

Example 1: Installing additional software for the HA cluster
  1. Install the High Availability pattern on all nodes

    suse01:~> zypper in --type pattern ha_sles
  2. Install the SAPHanaSR resource agents on all nodes

    suse01:~> zypper in SAPHanaSR SAPHanaSR-doc

Optionally the ClusterTools2 package can be installed. It contains cmdline tools for simplifying common administrative tasks.

For more information, see section Installation and Basic Setup of the SUSE Linux Enterprise High Availability Extension guide.

6 Installing the SAP HANA Databases on both Cluster Nodes

SAPHanaSR ScaleOut Plan Phase3

Even though this document focuses on the integration of an installed SAP HANA with system replication already set up into the pacemaker cluster, this chapter summarizes the test environment. Always use the official documentation from SAP to install SAP HANA and to set up the system replication.

6.1 Installing the SAP HANA Databases

Preparation
  • Read the SAP Installation and Setup Manuals available at the SAP Marketplace.

  • Download the SAP HANA Software from SAP Marketplace.

Actions
  1. Install the SAP HANA Database as described in the SAP HANA Server Installation Guide.

  2. Check if the SAP Host Agent is installed on all cluster nodes. If this SAP service is not installed, install it now.

  3. Verify that both databases (of the system replicated pair) are up and all processes of these databases are running correctly.

As Linux user <sid>adm use the command line tool HDB to get an overview of running HANA processes. The output of HDB info should be similar to the output shown below:

suse02:~> HDB info
USER           PID  ...  COMMAND
ha1adm         6561 ...  -csh
ha1adm         6635 ...    \_ /bin/sh /usr/sap/HA1/HDB10/HDB info
ha1adm         6658 ...        \_ ps fx -U ha1 -o user,pid,ppid,pcpu,vsz,rss,args
ha1adm         5442 ...  sapstart pf=/hana/shared/HA1/profile/HA1_HDB10_suse02
ha1adm         5456 ...   \_ /usr/sap/HA1/HDB10/suse02/trace/hdb.sapHA1_HDB10 -d
-nw -f /usr/sap/HA1/HDB10/suse
ha1adm         5482 ...       \_ hdbnameserver
ha1adm         5551 ...       \_ hdbpreprocessor
ha1adm         5554 ...       \_ hdbcompileserver
ha1adm         5583 ...       \_ hdbindexserver
ha1adm         5586 ...       \_ hdbstatisticsserver
ha1adm         5589 ...       \_ hdbxsengine
ha1adm         5944 ...       \_ sapwebdisp_hdb
pf=/usr/sap/HA1/HDB10/suse02/wdisp/sapwebdisp.pfl -f /usr/sap/SL
ha1adm         5363 ...  /usr/sap/HA1/HDB10/exe/sapstartsrv
pf=/hana/shared/HA1/profile/HA1_HDB10_suse02 -D -u s

6.2 Installing the Non-Replicated SAP HANA on the Secondary Site

  • Stop secondary (unlimited database)

  • Install the non-replicated SAP HANA with memory limits

  • Stop the non-replicated SAP HANA

Example 2: Check the memory limitations for the non-replicated SAP HANA
[memorymanager]
global_allocation_limit = <size_in_mb_for_non_replicated_hana>

7 Set Up SAP HANA System Replication

SAPHanaSR ScaleOut Plan Phase4

For more information read the section Setting Up System Replication of the SAP HANA Administration Guide.

Procedure

  1. Back up the primary database

  2. Enable primary database

  3. Register, limit and start the secondary database

  4. Verify the system replication

7.1 Backing Up the Primary Database

Back up the primary database as described in the SAP HANA Administration Guide, section SAP HANA Database Backup and Recovery. We provide an example with SQL commands. You need to adapt these backup commands to match your backup infrastructure.

Example 3: Simple backup for the system database and all tenants with one single backup call

As user <sid>adm enter the following command:

hdbsql -u SYSTEM -d SYSTEMDB \
   "BACKUP DATA FOR FULL SYSTEM USING FILE ('backup')"

You will get a command output similar to the following:

0 rows affected (overall time 15.352069 sec; server time 15.347745 sec)
Example 4: Simple backup for a single container (non MDC) database

Enter the following command as user <sid>adm:

hdbsql -i <instanceNumber> -u <dbuser> \
   "BACKUP DATA USING FILE ('backup')"
Important
Important

Without a valid backup, you cannot bring SAP HANA into a system replication configuration.

7.2 Enable Primary Node

As Linux user <sid>adm enable the system replication at the primary node. You need to define a site name (like WDF). This site name must be unique for all SAP HANA databases which are connected via system replication. This means the secondary must have a different site name.

Note
Note

Do not use strings like "primary" and "secondary" as site names.

Example 5: Enable the Primary

Enable the primary using the -sr_enable option.

suse01:~> hdbnsutil -sr_enable --name=WDF
checking local nameserver:
checking for active nameserver ...
nameserver is running, proceeding ...
configuring ini files ...
successfully enabled system as primary site ...
done.
Example 6: Check SR Configuration on the Primary

Check the primary using the command hdbnsutil -sr_stateConfiguration.

suse01:~> hdbnsutil -sr_stateConfiguration --sapcontrol=1
SAPCONTROL-OK: <begin>
mode=primary
site id=1
site name=WDF
SAPCONTROL-OK: <end>
done.

The mode has changed from “none” to “primary”. The site now has a site name and a site ID.

7.3 Register Secondary Node

The SAP HANA database instance on the secondary side must be stopped before the instance can be registered for the system replication. You can use your preferred method to stop the instance (like HDB or sapcontrol). After the database instance has been stopped successfully, you can register the instance using hdbnsutil. Again, use the Linux user <sid>adm:

Example 7: Stop the Secondary

To stop the secondary, you can use the command line tool HDB.

suse02:~> HDB stop
Example 8: Copy the KEY and KEY-DATA file from the primary to the secondary site

Beginning with SAP HANA 2.0, the system replication is running encrypted. The key files need to be copied-over from the primary to the secondary site.

cd /usr/sap/<SID>/SYS/global/security/rsecssfs
rsync -va {<node1-site A>:,}$PWD/data/SSFS_<SID>.DAT
rsync -va {<node1-site A>:,}$PWD/key/SSFS_<SID>.KEY
Example 9: Register the Secondary

The registration of the secondary is triggered by calling hdbnsutil -sr_register …​.

...
suse02:~> hdbnsutil -sr_register --name=ROT \
     --remoteHost=suse01 --remoteInstance=10 \
     --replicationMode=sync --operationMode=logreplay
adding site ...
checking for inactive nameserver ...
nameserver suse02:30001 not responding.
collecting information ...
updating local ini files ...
done.

The remoteHost is the primary node in our case, the remoteInstance is the database instance number (here 10).

Now start the database instance again and verify the system replication status. On the secondary node, the mode should be one of "SYNC" or "SYNCMEM". "ASYNC" is not supported with automated cluster takeover. The mode depends on the replicationMode option defined during the registration of the secondary.

Example 10: Set Memory Limits for the SAP HANA Secondary

Add the memory limits to the global.ini. Keep in mind that SUSE cannot provide a sizing guide here. SAP HANA sizing needs to be done according to respective SAP guidelines.

[memorymanager]
global_allocation_limit = <size_in_mb_for_secondary_hana>
Example 11: Switch table pre-load to off

To allow the SAP HANA secondary with less memory, you need to switch-off table pre-load.

[system_replication]
preload_column_tables = false
Example 12: Start Secondary and Check SR Configuration

To start the new secondary, use the command line tool HDB. Then check the SR configuration using hdbnsutil -sr_stateConfiguration.

suse02:~> HDB start
...
suse02:~> hdbnsutil -sr_stateConfiguration --sapcontrol=1
SAPCONTROL-OK: <begin>
mode=sync
site id=2
site name=ROT
active primary site=1
primary masters=suse01
SAPCONTROL-OK: <end>
done.

To view the replication state of the whole SAP HANA cluster, use the following command as <sid>adm user on the primary node.

Example 13: Checking System Replication Status Details

The python script systemReplicationStatus.py provides details about the current system replication.

suse01:~> HDBSettings.sh systemReplicationStatus.py --sapcontrol=1
...
site/2/SITE_NAME=ROT
site/2/SOURCE_SITE_ID=1
site/2/REPLICATION_MODE=SYNC
site/2/REPLICATION_STATUS=ACTIVE
site/1/REPLICATION_MODE=PRIMARY
site/1/SITE_NAME=WDF
local_site_id=1
...

7.4 Manual Test of SAP HANA SR Takeover

Before you integrate your SAP HANA system replication into the cluster, it is mandatory to do a manual takeover. Testing without the cluster helps to make sure that basic operation (takeover and registration) is working as expected.

  • Stop SAP HANA on node 1

  • Takeover SAP HANA to node 2

  • Register node 1 as secondary

  • Start SAP HANA on node 1

  • Wait until sync state is active

7.5 Optional: Manual Re-Establishment of SAP HANA SR to Original State

Bring the systems back to the original state:

  • Stop SAP HANA on node 2

  • Take over SAP HANA to node 1

  • Register node 2 as secondary

  • Start SAP HANA on node2

  • Wait until sync state is active

8 Set Up SAP HANA HA/DR Providers

SAPHanaSR ScaleOut Plan Phase5

This step is mandatory to inform the cluster immediately if the secondary gets out of sync. The hook is called by SAP HANA using the HA/DR provider interface in point-of-time when the secondary gets out of sync. This is typically the case when the first commit pending is released. The hook is called by SAP HANA again when the system replication is back.

Procedure

  1. Implement the python hook SAPHanaSR

  2. Configure system replication operation mode

  3. Allow <sid>adm to access the cluster

  4. Start SAP HANA

  5. Test the hook integration

Implement two SAP HANA HA/DR provider hooks. One hook is named SAPHanaSR and shipped with the SAPHanaSR package. The other is named srCostOptMemConfig and needs to be adopted to your database according to your specific username/password and connection.

The steps in this section must be performed on both sites. SAP HANA must be stopped to change the global.ini and allow SAP HANA to integrate the HA/DR hook script during start.

  • Install the HA/DR hook scripts into a read/writable directory

  • Integrate the hooks into global.ini (SAP HANA needs to be stopped)

  • Check integration of the hooks during start-up

8.1 Implementing SAPHanaSR Hook for srConnectionChanged

Use the hook from the SAPHanaSR package /usr/share/SAPHanaSR/SAPHanaSR.py. Optionally copy it to your preferred directory, such as /hana/shared/srHook/. The hook must be available on all SAP HANA cluster nodes.

Example 14: Stop SAP HANA

Stop SAP HANA either with HDB or using sapcontrol.

sapcontrol -nr <instanceNumber> -function StopSystem
Example 15: Adding SAPHanaSR via global.ini
[ha_dr_provider_SAPHanaSR]
provider = SAPHanaSR
path = /usr/share/SAPHanaSR/
execution_order = 1

[trace]
ha_dr_saphanasr = info

8.1.1 Configuring System Replication Operation Mode

When your system is connected as an SAPHanaSR target, you can find an entry in the global.ini which defines the operation mode. Up to now there are the following modes available:

  • delta_datashipping

  • logreplay

  • (logreplay_readaccess, not suitable for the cost optimized scenario)

Until a takeover and re-registration in the opposite direction, the entry for the operation mode is missing on your primary site. The first operation mode which was available was delta_datashipping. Today the preferred modes for HA are logreplay or logreplay_readaccess. Using the operation mode logreplay makes your secondary site in the SAP HANA system replication a hot standby system. For more details regarding all operation modes, check the available SAP documentation such as "How To Perform System Replication for SAP HANA ".

Example 16: Checking the Operation Mode

Check both global.ini files and add the operation mode if needed.

section

[ system_replication ]

entry

operation_mode = logreplay

Path for the global.ini: /hana/shared/<SID>/global/hdb/custom/config/

[system_replication]
operation_mode = logreplay

8.1.2 Allowing <sid>adm to Access the Cluster

The current version of the SAPHanaSR python hook uses the command sudo to allow the <sid>adm user to access the cluster attributes. In Linux you can use visudo to start the vi editor for the /etc/sudoers configuration file.

The user <sid>adm must be able to set the cluster attributes hana_<sid>_site_srHook_*. The SAP HANA system replication hook needs password free access. The following example limits the sudo access to exactly setting the needed attribute.

Replace the <sid> by the lowercase SAP system ID (like ha1).

Example 17: Entry in sudo permissions /etc/sudoers file

Basic sudoers entry to allow <sid>adm to use the srHook.

# SAPHanaSR-ScaleUp entries for writing srHook cluster attribute
<sid>adm ALL=(ALL) NOPASSWD: /usr/sbin/crm_attribute -n hana_<sid>_site_srHook_*

More specific sudoers entries to meet a high security level.

All Cmnd_Alias entries must be each defined as a single line entry. In our example we would have four separate lines with Cmnd_Alias entries, one line for the <sid>adm user and one or more lines for comments. In the document at hand, however, the separate lines of the example might include a line-break forced by document formatting.

# SAPHanaSR-ScaleUp entries for writing srHook cluster attribute
Cmnd_Alias SOK_SITEA   = /usr/sbin/crm_attribute -n hana_<sid>_site_srHook_<siteA> -v SOK   -t crm_config -s SAPHanaSR
Cmnd_Alias SFAIL_SITEA = /usr/sbin/crm_attribute -n hana_<sid>_site_srHook_<siteA> -v SFAIL -t crm_config -s SAPHanaSR
Cmnd_Alias SOK_SITEB   = /usr/sbin/crm_attribute -n hana_<sid>_site_srHook_<siteB> -v SOK   -t crm_config -s SAPHanaSR
Cmnd_Alias SFAIL_SITEB = /usr/sbin/crm_attribute -n hana_<sid>_site_srHook_<siteB> -v SFAIL -t crm_config -s SAPHanaSR
<sid>adm ALL=(ALL) NOPASSWD: SOK_SITEA, SFAIL_SITEA, SOK_SITEB, SFAIL_SITEB

8.2 Implementing Hook srCostOptMemConfig for srPostTakeover Method

The parameters added to global.ini imply that the hook srCostOptMemConfig needs to be installed on the second node. This document provides a sample code (see Section 13.4.3, “srCostOptMemConfig”) which needs to be adapted for your environment. Currently you need to provide a user name / password combination inside the hook. It is recommended to use a database user with minimum permissions.

Example 18: Installing srCostOptMemConfig.py

Copy the example, adapt it to your environment and set restrictive file permissions.

# cd /hana/shared/srHook
## copy the example from the appendix of this document
## set restricted file permissions
# chown <sid>adm.users srCostOptMemConfig.py
# chmod 500 srCostOptMemConfig.py

## change the connection setting to your local environment
# vi srCostOptMemConfig.py
dbuser="SYSTEM"
dbpwd="<yourPassword>"
dbinst="<yourInstanceNr>"
dbport="30013"

In the same directory (/hana/shared/srHook) you need to install (link) some Python files from the SAP HANA client software to enable the hook to run the database connect and SQL queries. You need the following files:

  • dbapi.py

  • __init__.py

  • resultrow.py

It is recommended to use symlink to have those Python libraries available. Using symlink, the files are always up to date if you update SAP HANA.

# cd /hana/shared/srHook
# ln -s /hana/shared/<SID>/exe/linuxx86_64/hdb/python_support/hdbcli/dbapi.py .
# ln -s /hana/shared/<SID>/exe/linuxx86_64/hdb/python_support/hdbcli/__init__.py .
# ln -s /hana/shared/<SID>/exe/linuxx86_64/hdb/python_support/hdbcli/resultrow.py .
Example 19: Enable use of srCostOptMemConfig

Enable the use of srCostOptMemConfig by adpating global.ini on node 2.

[ha_dr_provider_srCostOptMemConfig]
provider = srCostOptMemConfig
path = /hana/shared/srHook/
execution_order = 2

[trace]
ha_dr_saphanasr = info

After changing the global.ini on node 2 and implementing the srCostOptMemConfig hook, you should start the productive SAP HANA secondary database and check if the parameters are working.

As user <sid>adm on node 2, you might perform the following command:

suse02 > cdtrace
suse02 > grep  srCostOptMemConfig nameserver_*.trc

9 Configuration of the Cluster

SAPHanaSR ScaleOut Plan Phase6

This chapter describes the configuration of the cluster software SUSE Linux Enterprise High Availability Extension, which is part of SUSE Linux Enterprise Server for SAP Applications, and the SAP HANA Database integration.

Actions
  1. Basic Cluster Configuration

  2. Configuration of Cluster Properties and Resources

  3. Testing the Hook Integration

9.1 Basic Cluster Configuration

The first step is to set up the basic cluster framework. For convenience, use YaST2 or the ha-cluster-init script. It is strongly recommended to add a second corosync ring, change it to UCAST communication and adjust the timeout values to fit your environment.

9.1.1 Set up Watchdog for "Storage-Based Fencing"

If you use the storage-based fencing (SBD) mechanism (diskless or disk-based), you must also configure a watchdog. The watchdog is needed to reset a node if the system cannot longer access the SBD (diskless or disk-based). It is mandatory to configure the Linux system for loading a watchdog driver. It is strongly recommended to use a watchdog with hardware assistance (as is available on most modern systems), such as hpwdt, iTCO_wdt, or others. As fallback, you can use the softdog module.

Example 20: Setup for Watchdog
Important
Important

Access to the watchdog timer: No other software must access the watchdog timer; it can only be accessed by one process at any time. Some hardware vendors ship systems management software that use the watchdog for system resets (for example HP ASR daemon). Such software must be disabled if the watchdog is to be used by SBD.

Determine the right watchdog module. Alternatively, you can find a list of installed drivers with your kernel version.

ls -l /lib/modules/$(uname -r)/kernel/drivers/watchdog

Check if any watchdog module is already loaded.

lsmod | egrep "(wd|dog|i6|iT|ibm)"

If you get a result, the system has already a loaded watchdog. If the watchdog does not match your watchdog device, you need to unload the module.

To safely unload the module, check first if an application is using the watchdog device.

lsof /dev/watchdog
rmmod <wrong_module>

Enable your watchdog module and make it persistent. For the example below, softdog has been used. However, softdog has some restrictions and should not be used as first option.

echo softdog > /etc/modules-load.d/watchdog.conf
systemctl restart systemd-modules-load

Check if the watchdog module is loaded correctly.

lsmod | grep dog
ls -l /dev/watchdog

Testing the watchdog can be done with a simple action. Ensure to switch of your SAP HANA first because the watchdog will force an unclean reset or shutdown of your system.

In case a hardware watchdog is used, a desired action is predefined after the timeout of the watchdog has reached. If your watchdog module is loaded and not controlled by any other application, do the following:

Important
Important

Triggering the watchdog without continuously updating the watchdog resets/switches off the system. This is the intended mechanism. The following commands will force your system to be reset/switched off.

In case the softdog module is used, the following action can be performed:

sync; cat /dev/watchdog & while date; do sleep 10; done

After your test was successful, you must implement the watchdog on all cluster members.

9.1.2 Initial Cluster Setup Using ha-cluster-init

For more detailed information about setting up a cluster, refer to the sections Setting Up the First Node and Adding the Second Node of the Installation and Setup Quick Start for SUSE Linux Enterprise High Availability Extension 12.

Create an initial setup, using the ha-cluster-init command, and follow the dialogs. Do this only on the first cluster node.

suse01:~> ha-cluster-init -u -s <sbddevice>

This command configures the basic cluster framework including:

  • SSH keys

  • csync2 to transfer configuration files

  • SBD (at least one device)

  • corosync (at least one ring)

  • HAWK Web interface

Important
Important

As requested by ha-cluster-init, change the password of the user hacluster.

9.1.3 Adapting the Corosync and SBD Configuration

It is recommended to add a second corosync ring. If you did not start ha-cluster-init with the -u option, you need to change corosync to use UCAST communication. To change to UCAST, stop the already running cluster by using systemctl stop pacemaker. After the setup of the corosync configuration and the SBD parameters, start the cluster again.

9.1.3.1 Corosync Configuration

Check the following blocks in the file /etc/corosync/corosync.conf. See also the example at the end of this document.

totem {
    ...

    interface {
        ringnumber: 0
        mcastport:  5405
        ttl:        1
    }
    #Transport protocol
    transport:      udpu

}
nodelist {
        node {
            ring0_addr:     192.168.1.11
            nodeid: 1
        }
        node {
            ring0_addr:     192.168.1.12
            nodeid: 2
        }
    }
9.1.3.2 Adapting the SBD Configuration

You can skip this section if you do not have any SBD devices, but be sure to implement another supported fencing mechanism.

See the man pages sbd(8) and stonith_sbd(7) for details.

Table 3: SBD Options
ParameterDescription

SBD_WATCHDOG="yes"

Use watchdog. It is mandatory to use a watchdog. SBD does not work reliable without watchdog. Refer to the SLES manual and SUSE TIDs 7016880 for setting up a watchdog.

SBD_STARTMODE="clean"

Start mode. If set to one, sbd will only start if the node was previously shut down cleanly or if the slot is empty.

SBD_PACEMAKER="yes"

Check Pacemaker quorum and node health.

In the following example, replace /dev/disk/by-id/SBDA and /dev/disk/by-id/SBDB by your real SBD device names.

# /etc/sysconfig/sbd
SBD_DEVICE="/dev/disk/by-id/SBDA;/dev/disk/by-id/SBDB"
SBD_WATCHDOG_DEV="/dev/watchdog"
SBD_PACEMAKER="yes"
SBD_STARTMODE="clean"
SBD_OPTS=""

In your specific system, the file might have additional parameters not discussed here.

9.1.3.3 Verifying the SBD Device

You can skip this section if you do not have any SBD devices, but make sure to implement a supported fencing mechanism.

It is a good practice to check if the SBD device can be accessed from both nodes and does contain valid records. Check this for all devices configured in /etc/sysconfig/sbd. You can do so, for example, by calling cs_show_sbd_devices.

suse01:~ # sbd -d /dev/disk/by-id/SBDA dump
==Dumping header on disk /dev/disk/by-id/SBDA
Header version     : 2.1
UUID               : 0f4ea13e-fab8-4147-b9b2-3cdcfff07f86
Number of slots    : 255
Sector size        : 512
Timeout (watchdog) : 20
Timeout (allocate) : 2
Timeout (loop)     : 1
Timeout (msgwait)  : 40
==Header on disk /dev/disk/by-id/SBDA is dumped

The timeout values in our example are only start values. They need to be tuned to your environment.

To check the current SBD entries for the various cluster nodes, you can use sbd list. If all entries are clear, no fencing task is marked in the SBD device.

suse01:~ # sbd -d /dev/disk/by-id/SBDA list
0     suse01      clear

For more information on SBD configuration parameters, read the section Using SBD as Fencing Mechanism of the Installation and Setup Quick Start for SUSE Linux Enterprise High Availability Extension 12, and the TIDs 7016880 and 7008216.

Now it is time to restart the cluster at the first node again (systemctl start pacemaker).

9.1.4 Cluster Configuration on the Second Node

The second node of the two nodes cluster can be integrated by starting the command ha-cluster-join. This command asks for the IP address or name of the first cluster node. With this command, all needed configuration files are copied over. As a result, the cluster is started on both nodes.

# ha-cluster-join -c <host1>

9.1.5 Checking the Cluster for the First Time

Now it is time to check and optionally start the cluster for the first time on both nodes.

suse01:~ # systemctl status pacemaker
suse01:~ # systemctl status sbd
suse02:~ # systemctl status pacemaker
suse02:~ # systemctl status sbd
suse01:~ # systemctl start pacemaker
suse02:~ # systemctl start pacemaker

Check the cluster status. First, check if all nodes have used the SBD devices. To check the current SBD entries for the various cluster nodes, you can use sbd list. If all entries are clear , no fencing task is marked in the SBD device.

 suse01:~ # sbd -d /dev/disk/by-id/SBDA list
 0     suse01      clear
 1     suse02      clear

You can also call cs_show_sbd_devices again. Next, check if all nodes have joined the cluster. To do so, call crm_mon. Use the option "-r" to also see the resources that are configured but stopped.

# crm_mon -r

The command will show the "empty" cluster and will print something similar to the screen output below. The most interesting information for now is that there are two nodes in the status "online", and the message "partition with quorum".

Stack: corosync
Current DC: suse01 (version 1.1.19+20180928.0d2680780-1.8-1.1.19+20180928.0d2680780) - partition with quorum
Last updated: Fri Nov 29 12:41:16 2019
Last change: Fri Nov 29 12:40:22 2019 by root via crm_attribute on suse02
2 nodes configured
1 resource configured
Online: [ suse01 suse02 ]
Full list of resources:
 stonith-sbd    (stonith:external/sbd): Started suse01

9.2 Configuring Cluster Properties and Resources

This section describes how to configure constraints, resources, bootstrap, and STONITH, using the crm configure shell command as described in section Configuring and Managing Cluster Resources (Command Line) of the Administration Guide for SUSE Linux Enterprise High Availability Extension 12.

Use the command crm to add the objects to the cluster information base (CIB). Copy the following examples to a local file, edit the file and then load the configuration to the CIB:

suse01:~ # vi crm-fileXX
suse01:~ # crm configure load update crm-fileXX

9.2.1 Cluster Bootstrap and More

The first example defines the cluster bootstrap options, the resource and operation defaults. The stonith-timeout should be greater than 1.2 times the SBD msgwait timeout.

suse01:~ # vi crm-bs.txt
# enter the following to crm-bs.txt
property $id="cib-bootstrap-options" \
              stonith-enabled="true" \
              stonith-action="reboot" \
              stonith-timeout="150s"
rsc_defaults $id="rsc-options" \
              resource-stickiness="1000" \
              migration-threshold="3"
op_defaults $id="op-options" \
                 timeout="600"

Now add the configuration to the cluster.

suse01:~ # crm configure load update crm-bs.txt

9.2.2 STONITH Device

Skip this section if you are using diskless SBD.

The next configuration part defines an SBD disk STONITH resource with an appropriate value for the parameter_pcmk_delay_max_.

# vi crm-sbd.txt
# enter the following to crm-sbd.txt
primitive stonith-sbd stonith:external/sbd \
    params pcmk_delay_max="30"

Again, add the configuration to the cluster.

suse01:~ # crm configure load update crm-sbd.txt

For an advanced SBD setup, refer to the SUSE Linux Enterprise High Availability Extension product documentation (for example, visit https://documentation.suse.com/sle-ha/12-SP4/html/SLE-HA-all/cha-ha-storage-protect.html#pro-ha-storage-protect-fencing). If the preferred node running the primary HANA database always should win in case of split-brain, look up the "Predictable Static Delays" configuration example. See also Section 13.4.1, “Example for Deterministic SBD STONITH”.

For fencing with IPMI/ILO, see Section 9.2.3, “Using IPMI as Fencing Mechanism”.

9.2.3 Using IPMI as Fencing Mechanism

This section is only relevant if the recommended disk-based or diskless SBD fencing is not used.

For details about IPMI/ILO fencing, read the cluster product documentation (https://documentation.suse.com/sle-ha/12-SP4/html/SLE-HA-all/book-sleha.html). An example for an IPMI STONITH resource can be found in Section 13.4.2, “Example for the IPMI STONITH Method” of this document.

To use IPMI, the remote management boards must be compatible with the IPMI standard.

For the IPMI-based fencing, configure a primitive per-cluster node. Each resource is responsible to fence exactly one cluster node. Adapt the IP addresses and login user / password of the remote management boards to the STONITH resource agent. We recommend to create a special STONITH user instead of providing root access to the management board. Location rules must guarantee that a host should never run its own STONITH resource.

9.2.4 Using Other Fencing Mechanisms

This section is only relevant if the recommended disk-based or diskless SBD fencing is not used.

We recommend to use SBD (best practice) or IPMI (second choice) as STONITH mechanism. The SUSE Linux Enterprise High Availability Extension product also supports additional fencing mechanism not covered here.

For further information about fencing, read the Administration Guide for SUSE Linux Enterprise High Availability Extension at https://documentation.suse.com/sle-ha/12-SP4/html/SLE-HA-all/book-sleha.html.

9.2.5 SAPHanaTopology

This step is to define the resources needed, to analyze the SAP HANA topology for the replicated pair. Prepare the changes in a text file, for example crm-saphanatop.txt, and load it with the command:

crm configure load update crm-saphanatop.txt

# vi crm-saphanatop.txt
# enter the following to crm-saphanatop.txt
primitive rsc_SAPHanaTopology_HA1_HDB10 ocf:suse:SAPHanaTopology \
        op monitor interval="10" timeout="600" \
        op start interval="0" timeout="600" \
        op stop interval="0" timeout="300" \
        params SID="HA1" InstanceNumber="10"
clone cln_SAPHanaTopology_HA1_HDB10 rsc_SAPHanaTopology_HA1_HDB10 \
        meta clone-node-max="1" interleave="true"

Additional information about all parameters can be found with the command:

man ocf_suse_SAPHanaTopology

Again, add the configuration to the cluster.

suse01:~ # crm configure load update crm-saphanatop.txt

The most important parameters here are SID and InstanceNumber, which are quite self explaining in the SAP context. Beside these parameters, typical tuneables are the timeout values or the operations (start, monitor, stop).

9.2.6 SAPHana

This step is to define the resource needed, to control the replicated SAP HANA pair. Edit the changes in a text file, for example crm-saphana.txt, and load it with the following command:

crm configure load update crm-saphana.txt

Table 4: Typical Resource Agent parameter settings for different scenarios
ParameterPerformance OptimizedCost OptimizedMulti-Tier

PREFER_SITE_TAKEOVER

true

false

false / true

AUTOMATED_REGISTER

false / true

false / true

false

DUPLICATE_PRIMARY_TIMEOUT

7200

7200

7200

Table 5: Description of important Resource Agent parameters
ParameterDescription

PREFER_SITE_TAKEOVER

Defines whether RA should prefer to takeover to the secondary instance instead of restarting the failed primary locally.

AUTOMATED_REGISTER

Defines whether a former primary should be automatically registered to be secondary of the new primary. With this parameter you can adapt the level of system replication automation.

If set to false, the former primary must be manually registered. The cluster will not start this SAP HANA RDBMS until it is registered, to avoid double primary up situations.

DUPLICATE_PRIMARY_TIMEOUT

Time difference needed between two primary time stamps if a dual-primary situation occurs. If the time difference is less than the time gap, the cluster holds one or both instances in a "WAITING" status. This is to give an administrator the chance to react on a fail-over. If the complete node of the former primary crashed, the former primary will be registered after the time difference is passed. If "only" the SAP HANA RDBMS has crashed, the former primary will be registered immediately. After this registration to the new primary, all data will be overwritten by the system replication.

Additional information about all parameters can be found with the following command:

man ocf_suse_SAPHana

# vi crm-saphana.txt
# enter the following to crm-saphana.txt
primitive rsc_SAPHana_HA1_HDB10 ocf:suse:SAPHana \
        op start interval="0" timeout="3600" \
        op stop interval="0" timeout="3600" \
        op promote interval="0" timeout="3600" \
        op monitor interval="60" role="Master" timeout="700" \
        op monitor interval="61" role="Slave" timeout="700" \
        params SID="HA1" InstanceNumber="10" PREFER_SITE_TAKEOVER="false" \
        DUPLICATE_PRIMARY_TIMEOUT="7200" AUTOMATED_REGISTER="false"
ms msl_SAPHana_HA1_HDB10 rsc_SAPHana_HA1_HDB10 \
        meta clone-max="2" clone-node-max="1" interleave="true"

Now add the configuration to the cluster.

suse01:~ # crm configure load update crm-saphana.txt

The most important parameters here are again SID and InstanceNumber. Beside these parameters, typical tuneables are the timeout values for the operations (start, promote, monitors, stop). The parameter AUTOMATED_REGISTER can be used to adapt the level of system replication automation.

9.2.7 Virtual IP Address for the Primary Site

The last resource to be added for SAPHanaSR is covering the virtual IP address.

# vi crm-vip.txt
# enter the following to crm-vip.txt

primitive rsc_ip_HA1_HDB10 ocf:heartbeat:IPaddr2 \
        op monitor interval="10s" timeout="20s" \
        params ip="192.168.1.20"

Load the file to the cluster.

suse01:~ # crm configure load update crm-vip.txt

In most on-premise installations, only the parameter ip needs to be set to the virtual IP address to be presented to the client systems. Public cloud environments often need specific settings.

9.2.8 Constraints for SAPHanaSR

Two constraints are organizing the correct placement of the virtual IP address for the client database access and the start order between the two resource agents SAPHana and SAPHanaTopology.

# vi crm-cs.txt
# enter the following to crm-cs.txt
colocation col_saphana_ip_HA1_HDB10 2000: rsc_ip_HA1_HDB10:Started \
    msl_SAPHana_HA1_HDB10:Master
order ord_SAPHana_HA1_HDB10 Optional: cln_SAPHanaTopology_HA1_HDB10 \
    msl_SAPHana_HA1_HDB10

Load the file to the cluster.

suse01:~ # crm configure load update crm-cs.txt

9.2.9 Adding the Cluster Resource for the Non-Replicated SAP HANA Database

For the non-replicated SAP HANA database, a new resource is added to the cluster. In previous versions of this document we used the resource agent SAPDatabase to control that database. The new architecture now uses SAPInstance to start, stop and monitor this cluster component. The reason for that change is that SAPDatabase is using the SAP host agent API. The SAP host agent itself needs user secure keys to communicate with the cluster. This configuration is too complex and error-prone. SAPInstance uses the sapstartsrv API to do the work. This should solve the issue. The new concept has already been published in a SUSE towardsZeroDoentime blog at: https://suse.com/c/sap-hana-cost-optimized-an-alternative-route-is-available/

# vi crm-si.txt
# enter the following to crm-si.txt
primitive rsc_SAP_QAS_HDB20 ocf:heartbeat:SAPInstance \
  params InstanceName="QAS_HDB20_suse02" \
        MONITOR_SERVICES="hdbindexserver|hdbnameserver" \
        START_PROFILE="/usr/sap/QAS/SYS/profile/QAS_HDB20_suse02" \
  op start interval="0" timeout="600" \
  op monitor interval="120" timeout="700" \
  op stop interval="0" timeout="300" \
  meta priority="100"

Load the resource definition into the cluster

suse01:~ # crm configure load update crm-si.txt

9.2.10 Adding Cluster Rules for Automatic Shutdown of the Non-Replicated SAP HANA

In the following example, again suse01 and suse02 are used as the two active cluster nodes.

# vi crm-con.txt
# enter the following to crm-con.txt
location loc_QAS_never_on_suse01 rsc_SAP_QAS_HDB20 -inf: suse01
colocation col_QAS_never_with_HA1ip -inf: rsc_SAP_QAS_HDB20:Started \
  rsc_ip_HA1_HDB10
order ord_QASstop_before_HA1-promote mandatory: rsc_SAP_QAS_HDB20:stop \
  msl_SAPHana_HA1_HDB10:promote

Load the resource definition into the cluster

suse01:~ # crm configure load update crm-con.txt

10 Testing the Cluster

SAPHanaSR ScaleOut Plan Phase7

The lists of tests will be further enhanced with a next update of this document.

For any cluster setup testing is crucial. Make sure that all test cases derived from your organizations or from customer expectations are fully implemented and successfully passed. Otherwise the project is likely to fail in production.

If not described differently, the test prerequisite is always that both nodes are booted, normal members of the cluster and that the HANA RDBMS is running. There are no left-over migration constraints or resource failures contained in the cluster information base (CIB). The system replication is in sync (SOK).

This can be checked, for example, with the following command sequence:

 # crm_mon -1r
 # crm configure show | grep cli-
 # SAPHanaSR-showAttr
 # cs_clusterstate -i

See also the manual pages SAPHanaSR-showAttr(8), crm_mon(8), crm(8), cs_clusterstate(8), SAPHanaSR_maintenance_examples(7).

10.1 Test Cases for Semi-Automation

For the following test descriptions, we assume the following parameter values: * PREFER_SITE_TAKEOVER="false" * AUTOMATED_REGISTER="false".

Note
Note

The following tests are designed to run in a sequence. Each test depends on the exit state of the preceding tests.

10.1.1 Tests for Primary Database or Node

10.1.1.1 Test: Stop Primary Database on Site A (Node 1)
Example 21: Test STOP_PRIMARY_DB_SITE_A_SEMI
Component:
  • Primary Database

Description:
  • Stop Primary on site A (node 1)

Test Procedure:
  1. Stop the SAP HANA database as user <sid>adm

    suse01# HDB stop
Expected:
  • Primary restarts on site A (PREFER_SITE_TAKEOVER=false) until failcount >= migration-threshold

  • If takeover occurs:

    • non-replicated database is stopped on node 2 (site B)

    • Secondary database is promoted as primary

Recovery Procedure:
  • No recovery needed, if no takeover did occur

  • Recovery after takeover:

    1. Register site A to site B

    2. Resource cleanup for site A

10.1.1.2 Test: Stop Primary Database on Site B (Node 2)
Example 22: Test STOP_PRIMARY_DB_SITE_B_SEMI
Component:
  • Primary Database

Description:
  • Stop Primary on site B (node 2)

Test Procedure:
  1. Stop the SAP HANA database as user <sid>adm

    suse01# HDB stop
Expected:
  • Primary restarts on site B (PREFER_SITE_TAKEOVER=false) until failcount >= migration-threshold

  • Non-replicated database still stopped on node 2 (site B)

  • If takeover occurs:

    • Secondary database is promoted as primary

    • non-replicated database is started on node 2 (site B)

Recovery Procedure:
  • No recovery needed if no takeover did occur

  • Recovery after takeover:

    1. Register site B to site A

    2. Resource cleanup for site B

10.1.1.3 Test: Crash Primary Database on Site A (Node 1)
Example 23: Test CRASH_PRIMARY_DB_SITE_A_SEMI
Component:
  • Primary Database

Description:
  • Kill Primary on site A (node 1)

Test Procedure:
  1. Kill (send signal to) the SAP HANA database as user <sid>adm

    suse01# HDB kill-9
Expected:
  • Primary restarts on site A (PREFER_SITE_TAKEOVER=false) until failcount >= migration-threshold

  • If takeover occurs:

    • Non-replicated database is stopped on node 2 (site B)

    • Secondary database is promoted as primary

Recovery Procedure:
  • No recovery needed if no takeover did occur

  • Recovery after takeover:

    1. Register site A to site B

    2. Resource cleanup for site A

10.1.1.4 Test: Crash Primary Database on Site B (Node 2)
Example 24: Test CRASH_PRIMARY_DB_SITE_B_SEMI
Component:
  • Primary Database

Description:
  • Kill Primary on site B (node 2)

Test Procedure:
  1. Kill Primary on site B (node 2) as user <sid>adm

    suse02# HDB kill-9
Expected:
  • Primary restarts on site B (PREFER_SITE_TAKEOVER=false) until failcount >= migration-threshold

  • Non-replicated database still stopped on node 2 (site B)

Recovery Procedure:
  • No recovery needed if no takeover did occur

  • Recovery after takeover:

    1. Register site B to site A

    2. Resource cleanup for site B

10.1.1.5 Test: Crash Primary Node on Site A (Node 1)
Example 25: Test CRASH_PRIMARY_NODE_SITE_A_SEMI
Component:
  • Cluster Node

Description:
  • Crash node 1 (site A)

Test Procedure:
  1. Crash the node by proc-sysrq-trigger as user root

    suse01# sync; echo b > /proc/sysrq-trigger
Expected:
  • Non-replicated SAP HANA stopped on node 2

  • Cluster takeover to site B

  • Non-replicated database is stopped on node 2 (site B)

  • Secondary database is promoted as primary

Recovery Procedure:
  • Recovery after takeover:

    1. Optionally clean up sbd slot for node 1

    2. Start cluster framework on node 1

    3. Wait until node 1 joins the cluster

    4. Register site A to site B

10.1.1.6 Test: Crash Primary Node on Site B (Node 2)
Example 26: Test CRASH_PRIMARY_NODE_SITE_B_SEMI
Component:
  • Cluster Node

Description:
  • Crash node 2 (site B)

Test Procedure:
  1. Crash the node by proc-sysrq-trigger as user root

    suse02# sync; echo b > /proc/sysrq-trigger
Expected:
  • Cluster takeover to site A

  • Non-replicated database not available (no takeover to site A)

Recovery Procedure:
  • Recovery after takeover:

    1. Optionally clean up sbd slot for node 2

    2. Start cluster framework on node 2

    3. Wait until node 2 joins the cluster

    4. Register site B to site A

10.1.2 Tests for Secondary Database or Node

10.1.2.1 Test: Stop the Secondary Database on Site B (Node 2)
Example 27: Test STOP_SECONDARY_DB_SITE_B_SEMI
Component:
  • Secondary Database

Description:
  • Stop secondary database on node 2 (site B)

Test Procedure:
  1. Stop the secondary SAP HANA database as user <sid>adm

    suse02# HDB stop
Expected:
  • Cluster restarts Secondary on node 2 (site B)

  • non-replicated database not affected on node 2 (site B)

Recovery Procedure:
  1. Wait and see

  2. Resource cleanup for site B

10.1.2.2 Test: Crash the Secondary Database on Site B (Node 2)
Example 28: Test CRASH_SECONDARY_DB_SITE_B_SEMI
Component:
  • Secondary Database

Description:
  • Crash secondary database on node 2 (site B)

Test Procedure:
  1. Kill (send signal to) the secondary SAP HANA database as user <sid>adm

    suse02# HDB kill-9
Expected:
  • Cluster restarts Secondary on node 2 (site B)

  • Non-replicated database not affected on node 2 (site B)

Recovery Procedure:
  1. Wait and see

  2. Resource cleanup for site B

10.1.2.3 Test: Crash the Secondary Node on Site B (Node2)
Example 29: Test CRASH_SECONDARY_NODE_SITE_B_SEMI
Component:
  • Cluster Node

Description:
  • Crash node 2 (site B)

Test Procedure:
  1. Crash the node by proc-sysrq-trigger as user root

    suse02# sync; echo b > /proc/sysrq-trigger
Expected:
  • No takeover of node 2 resources to site A

  • Non-replicated database not available (no takeover to site A)

Recovery Procedure:
  • Recovery after node 2 is back:

    1. Optionally clean up sbd slot for node 2

    2. Start cluster framework on node 2

    3. Wait until node 2 joins the cluster

10.1.3 Tests for Non-Replicated Database

10.1.3.1 Test: Stop Non-Replicated Database on SiteB (Node 2)
Example 30: Test STOP_NONSR_DB_SITE_B_SEMI
Component:
  • Non-Replicated Database

Description:
  • Stop non-replicated database node 2 (site B)

Test Procedure:
  1. Kill (send signal to) the secondary SAP HANA database as user <sid>adm

    suse02# HDB stop
Expected:
  • Cluster restarts non-replicated database on node 2 (site B)

  • Secondary database is not affected

Recovery Procedure:
  1. Clean up non-replicated database resource

10.1.3.2 Test: Crash Non-Replicated Database on Site B (Node 2)
Example 31: Test CRASH_NONSR_DB_SITE_B_SEMI
Component:
  • Non-Replicated Database

Description:
  • Crash non-replicated database on node 2 (site B)

Test Procedure:
  1. Kill (send signal to) the non-replicated SAP HANA database as user <sid>adm

    suse02# HDB kill-9
Expected:
  • Cluster restarts non-replicated database on node 2 (site B)

  • Secondary database is not affected

Recovery Procedure:
  1. Clean up non-replicated database resource

10.1.4 Tests for Other Components

10.1.4.1 Test: Failure of Dedicated Replication LAN
Example 32: Test FAIL_NETWORK_SR_SEMI
Component:
  • Replication Network

Description:
  • Pull LAN port down or block network packets for system replication. Corosync network still available.

Expected:
  • System replication status fall down to status SFAIL

  • Primary stays on node 1 (site A)

  • No cluster takeover

  • Non-replicated database not affected on node 2 (site B)

Recovery Procedure:
  1. Reestablish network connection

  2. Wait until System replication status is SOK again

10.1.5 Test Maintenance Procedures

Also test the maintenance procedures mentioned in section Section 11.3, “Maintenance”.

10.2 Test Cases for Full Automation

For the following test descriptions, we assume the following parameter values: * PREFER_SITE_TAKEOVER="false" * AUTOMATED_REGISTER="true".

Note
Note

The following tests are designed to run in a sequence. Each test depends on the exit state of the preceding tests.

10.2.1 Tests for Primary Database or Node

10.2.1.1 Test: Stop Primary Database on Site A (Node 1)
Example 33: Test STOP_PRIMARY_DB_SITE_A_FULL
Component:
  • Primary Database

Description:
  • Stop primary database on site A (node 1)

Test Procedure:
  1. Stop the SAP HANA database as user <sid>adm

    suse01# HDB stop
Expected:
  • Primary restarts on site A (PREFER_SITE_TAKEOVER=false) until failcount >= migration-threshold

  • If takeover occurs:

    • Non-replicated database is stopped on node 2 (site B)

    • Secondary database is promoted as primary

    • SiteA is automatically registered to SiteB

Recovery Procedure:
  • No recovery needed, if no takeover did occur

  • Recovery after takeover:

    1. Resource cleanup for site A

10.2.1.2 Test: Stop Primary Database on Site B (Node 2)
Example 34: Test STOP_PRIMARY_DB_SITE_B_FULL
Component:
  • Primary Database

Description:
  • Stop primary database on site B (node 2)

Test Procedure:
  1. Stop the SAP HANA database as user <sid>adm

    suse01# HDB stop
Expected:
  • Primary restarts on site B (PREFER_SITE_TAKEOVER=false) until failcount >= migration-threshold

  • Non-replicated database still stopped on node 2 (site B)

  • If takeover occurs:

    • Secondary database is promoted as primary

    • non-replicated database is started on node 2 (site B)

    • SiteB is automatically registered to SiteA

Recovery Procedure:
  • No recovery needed if no takeover did occur

  • Recovery after takeover:

    1. Resource cleanup for site B

10.2.1.3 Test: Crash Primary Database on Site A (Node 1)
Example 35: Test CRASH_PRIMARY_DB_SITE_A_FULL
Component:
  • Primary Database

Description:
  • Kill primary database on site A (node 1)

Test Procedure:
  1. Kill (send signal to) the SAP HANA database as user <sid>adm

    suse01# HDB kill-9
Expected:
  • Primary restarts on site A (PREFER_SITE_TAKEOVER=false) until failcount >= migration-threshold

  • If takeover occurs:

    • Non-replicated database is stopped on node 2 (site B)

    • Secondary database is promoted as primary

    • SiteA is registered to SiteB

Recovery Procedure:
  • No recovery needed if no takeover did occur

  • Recovery after takeover:

    1. Resource cleanup for site A

10.2.1.4 Test: Crash Primary Database on Site B (Node 2)
Example 36: Test CRASH_PRIMARY_DB_SITE_B_FULL
Component:
  • Primary Database

Description:
  • Kill primary database on site B (node 2)

Test Procedure:
  1. Kill primary database on site B (node 2) as user <sid>adm

    suse02# HDB kill-9
Expected:
  • Primary restarts on site B (PREFER_SITE_TAKEOVER=false) until failcount >= migration-threshold

  • Non-replicated database still stopped on node 2 (site B)

  • If takeover occurs:

    • Secondary database is promoted as primary

    • Non-replicated database is started on node 2 (site B)

    • SiteB is automatically registered to SiteA

Recovery Procedure:
  • No recovery needed if no takeover did occur

  • Recovery after takeover:

    1. Resource cleanup for site B

10.2.1.5 Test: Crash Primary Node on Site A (Node 1)
Example 37: Test CRASH_PRIMARY_NODE_SITE_A_FULL
Component:
  • Cluster Node

Description:
  • Crash node 1 (site A)

Test Procedure:
  1. Crash the node by proc-sysrq-trigger as user root

    suse01# sync; echo b > /proc/sysrq-trigger
Expected:
  • Non-replicated SAP HANA stopped on node 2

  • Cluster takeover to site B

  • Non-replicated database is stopped on node 2 (site B)

  • Secondary database is promoted as primary

  • Later, when node 1 joins the cluster again:

    • SiteA is registered to SiteB

Recovery Procedure:
  • Recovery after takeover:

    1. Optionally clean up sbd slot for node 1

    2. Start cluster framework on node 1

    3. Wait until node 1 joins the cluster

10.2.1.6 Test: Crash Primary Node on Site B (Node 2)
Example 38: Test CRASH_PRIMARY_NODE_SITE_B_FULL
Component:
  • Cluster Node

Description:
  • Crash node 2 (site B) as user root

Test Procedure:
  1. Crash the node by proc-sysrq-trigger

    suse02# sync; echo b > /proc/sysrq-trigger
Expected:
  • Cluster takeover to site A

  • Non-replicated database not available (no takeover to site A)

  • Later, when node 2 joins the cluster again:

    • SiteB is registered to SiteA

    • Non-replicated database will be started

Recovery Procedure:
  • Recovery after takeover:

    1. Optionally clean up sbd slot for node 2

    2. Start cluster framework on node 2

    3. Wait until node 2 joins the cluster

10.2.2 Tests for Secondary Database or Node

10.2.2.1 Test: Stop the Secondary Database on Site B (Node 2)
Example 39: Test STOP_SECONDARY_DB_SITE_B_FULL
Component:
  • Secondary Database

Description:
  • Stop secondary database on node 2 (site B)

Test Procedure:
  1. Stop the secondary SAP HANA database as user <sid>adm

    suse02# HDB stop
Expected:
  • Cluster restarts Secondary on node 2 (site B)

  • Non-replicated database not affected on node 2 (site B)

Recovery Procedure:
  1. Wait and see

  2. Resource cleanup for site B

10.2.2.2 Test: Crash the Secondary Database on Site B (Node 2)
Example 40: Test CRASH_SECONDARY_DB_SITE_B_FULL
Component:
  • Secondary Database

Description:
  • Crash secondary database on node 2 (site B)

Test Procedure:
  1. Kill (send signal to) the secondary SAP HANA database as user <sid>adm

    suse02# HDB kill-9
Expected:
  • Cluster restarts Secondary on node 2 (site B)

  • Non-replicated database not affected on node 2 (site B)

Recovery Procedure:
  1. Wait and see

  2. Resource cleanup for site B

10.2.2.3 Test: Crash the Secondary Node on Site B (Node2)
Example 41: Test CRASH_SECONDARY_NODE_SITE_B_FULL
Component:
  • Cluster Node

Description:
  • Crash node 2 (site B)

Test Procedure:
  1. Crash the node by proc-sysrq-trigger as user root

    suse02# sync; echo b > /proc/sysrq-trigger
Expected:
  • No takeover of node 2 resources to site A

  • Non-replicated database not available (no takeover to site A)

Recovery Procedure:
  • Recovery after node 2 is back:

    1. Optionally clean up sbd slot for node 2

    2. Start cluster framework on node 2

    3. Wait until node 2 joins the cluster

10.2.3 Tests for Non-Replicated Database

10.2.3.1 Test: Stop Non-Replicated Database on SiteB (Node 2)
Example 42: Test STOP_NONSR_DB_SITE_B_FULL
Component:
  • Non-Replicated Database

Description:
  • Stop non-replicated database node 2 (site B)

Test Procedure:
  1. Kill (send signal to) the secondary SAP HANA database as user <sid>adm

    suse02# HDB stop
Expected:
  • Cluster restarts non-replicated database on node 2 (site B)

  • Secondary database is not affected

Recovery Procedure:
  1. Clean up non-replicated database resource

10.2.3.2 Test: Crash Non-Replicated Database on Site B (Node 2)
Example 43: Test CRASH_NONSR_DB_SITE_B_FULL
Component:
  • Non-Replicated Database

Description:
  • Crash non-replicated database on node 2 (site B)

Test Procedure:
  1. Kill (send signal to) the non-replicated SAP HANA database as user <sid>adm

    suse02# HDB kill-9
Expected:
  • Cluster restarts non-replicated database on node 2 (site B)

  • Secondary database is not affected

Recovery Procedure:
  1. Clean up non-replicated database resource

10.2.4 Tests for Other Components

10.2.4.1 Test: Failure of Dedicated Replication LAN
Example 44: Test FAIL_NETWORK_SR_FULL
Component:
  • Replication Network

Description:
  • Pull LAN port down or block network packets for system replication, Corosync network still available.

Expected:
  • System replication status fall down to status SFAIL

  • Primary stays on node 1 (site A)

  • No cluster takeover

  • Non-replicated database not affected on node 2 (site B)

Recovery Procedure:
  1. Reestablish network connection

  2. Wait until system replication status is SOK again

10.2.5 Test Maintenance Procedures

Also, test the maintenance procedures mentioned in section Section 11.3, “Maintenance”.

11 Administration

11.1 Dos and Don’ts

In your project, you should:

  • define STONITH before adding other resources to the cluster.

  • do intensive testing.

  • tune the timeouts of operations of SAPHana and SAPHanaTopology.

  • start with the parameter values PREFER_SITE_TAKEOVER=”false”, AUTOMATED_REGISTER=”false” and DUPLICATE_PRIMARY_TIMEOUT=”7200”.

  • set up a test cluster for testing configuration changes and administrative procedure before applying them on the production cluster.

In your project, avoid:

  • rapidly changing/changing back a cluster configuration, such as setting nodes to standby and online again or stopping/starting the multi-state resource.

  • creating a cluster without proper time synchronization or unstable name resolutions for hosts, users and groups.

  • adding location rules for the clone, multi-state or IP resource. Only location rules mentioned in this setup guide are allowed. For public cloud refer to the cloud specific documentation.

  • using SAP tools for attempting start/stop/takeover actions on a database while the cluster is in charge of managing that database.

Important
Important

As "migrating" or "moving" resources in crm-shell, HAWK or other tools would add client-prefer location rules, support is limited to maintenance procedures described in this document. See Section 10, “Testing the Cluster” and Section 11.3, “Maintenance” for proven procedures.

11.2 Monitoring and Tools

You can use the High Availability Web Console (HAWK), SAP HANA Studio and different command line tools for cluster status requests.

11.2.1 HAWK – Cluster Status and more

You can use a Web browser to check the cluster status.

SAPHanaSR ScaleUp HAWK Status SLE12
Figure 10: Cluster Status in HAWK

If you set up the cluster using ha-cluster-init and you have installed all packages as described above, your system will provide a very useful Web interface. You can use this graphical Web interface to get an overview of the complete cluster status, perform administrative tasks or configure resources and cluster bootstrap parameters. Read the product manuals for a complete documentation of this user interface. For the SAP HANA system replication cost optimized scenario the use of HAWK should follow the guidance given in this guide.

11.2.2 SAP HANA Studio

Database-specific administration and checks can be done with SAP HANA studio. Before trying start/stop/takeover for the database, make sure the cluster is not in charge of managing the respective resource. See also Section 11.3, “Maintenance”.

hana studio landscape
Figure 11: SAP HANA Studio – Landscape

11.2.3 Cluster Command Line Tools

A simple overview can be obtained by calling crm_mon. Using option -r shows also stopped but already configured resources. Option -1 tells crm_mon to output the status once instead of periodically.

Stack: corosync
Current DC: suse01 (version 1.1.19+20180928.0d2680780-1.8-1.1.19+20180928.0d2680780) - partition with quorum
Last updated: Fri Sep 13 11:55:12 2020
Last change: Fri Sep 13 11:55:06 2020 by root via crm_attribute on suse02

2 nodes configured
6 resources configured

Online: [ suse01 suse02 ]

Full list of resources:

 rsc_stonith_sbd    (stonith:external/sbd): Started suse01
 rsc_SAPInst_QAS_HDB20      (ocf::heartbeat:SAPInstance):   Started suse02
 Clone Set: cln_SAPHanaTopology_HA1_HDB10 [rsc_SAPHanaTopology_HA1_HDB10]
     Started: [ suse01 suse02 ]
 Master/Slave Set: msl_SAPHana_HA1_HDB10 [rsc_SAPHana_HA1_HDB10]
     Masters: [ suse01 ]
     Slaves: [ suse02 ]
 rsc_ip_HA1_HDB10       (ocf::heartbeat:IPaddr2):       Started suse01

See the manual page crm_mon(8) for details. If you have installed the ClusterTools2 package, also have a look at manual pages cs_clusterstate(8) and cs_show_hana_info(8).

11.2.4 SAPHanaSR Command Line Tools

To show some SAPHana or SAPHanaTopology resource agent internal values, call the program SAPHanaSR-showAttr. The internal values, the storage location and their parameter names may change in a next version of this document. The command SAPHanaSR-showAttr will always fetch the values from the correct storage location.

Do not use cluster commands like crm_attribute to fetch the values directly from the cluster. If you use such commands, your methods will be broken when you need to move an attribute to a different storage place or even out of the cluster. At first SAPHanaSR-showAttr is a test program only and should not be used for automated system monitoring.

 suse01:~ # SAPHanaSR-showAttr
 Host \ Attr clone_state remoteHost roles       ... site    srmode sync_state ...
 ---------------------------------------------------------------------------------
 suse01      PROMOTED    suse02     4:P:master1:... WDF      sync  PRIM       ...
 suse02      DEMOTED     suse01     4:S:master1:... ROT      sync  SOK        ...

SAPHanaSR-showAttr also supports other output formats such as script. The script format is intended to allow running filters. The SAPHanaSR package beginning with version 0.153 additionally provides a filter engine SAPHanaSR-filter. Combining SAPHanaSR-showAttr with output format script and SAPHanaSR-filter, you can define effective queries:

suse01:~ # SAPHanaSR-showAttr --format=script | \
   SAPHanaSR-filter --search='remote'
Mon Nov 11 20:55:45 2019; Hosts/suse01/remoteHost=suse02
Mon Nov 11 20:55:45 2019; Hosts/suse02/remoteHost=suse01

SAPHanaSR-replay-archive can help to analyze the SAPHanaSR attribute values from hb_report (crm_report) archives. This allows post mortem analyses.

In our example, the administrator killed the primary SAP HANA instance using the command HDB kill-9. This happened around 9:10 pm.

suse01:~ # hb_report -f 19:00
INFO: suse01# The report is saved in ./hb_report-1-11-11-2019.tar.bz2
INFO: suse01# Report timespan: 11/11/19 19:00:00 - 11/11/19 21:05:33
INFO: suse01# Thank you for taking time to create this report.
suse01:~ # SAPHanaSR-replay-archive --format=script \
    ./hb_report-1-11-11-2019.tar.bz2 | \
    SAPHanaSR-filter --search='roles' --filterDouble
Mon Nov 11 20:38:01 2019; Hosts/suse01/roles=4:P:master1:master:worker:master
Mon Nov 11 20:38:01 2019; Hosts/suse02/roles=4:S:master1:master:worker:master
Mon Nov 11 21:11:37 2019; Hosts/suse01/roles=1:P:master1::worker:
Mon Nov 11 21:12:43 2019; Hosts/suse02/roles=4:P:master1:master:worker:master

In the above example the attributes indicate that at the beginning suse01 was running primary (4:P) and suse02 was running secondary (4:S).

At 21:11 (CET) suddenly the primary on suse01 died - it was falling down to 1:P.

The cluster did jump in and initiated a takeover. At 21:12 (CET) the former secondary was detected as new running master (changing from 4:S to 4:P). See manual pages SAPHanaSR-showAttr(8), SAPHanaSR-replay-archive(8) and crm_report(8) for more information.

11.2.5 SAP HANA LandscapeHostConfiguration

To check the status of an SAPHana database and to find out if the cluster should react, use the script landscapeHostConfiguration as Linux user <sid>adm.

suse01:~> HDBSettings.sh landscapeHostConfiguration.py
| Host   | Host   | ... NameServer   | NameServer  | IndexServer | IndexServer |
|        | Active | ... Config Role  | Actual Role | Config Role | Actual Role |
| ------ | ------ | ... ------------ | ----------- | ----------- | ----------- |
| suse01 | yes    | ... master 1     | master      | worker      | master      |

overall host status: ok

Following the SAP HA guideline, the SAPHana resource agent interprets the return codes in the following way:

Table 6: Interpretation of Return Codes
Return CodeInterpretation

4

SAP HANA database is up and OK. The cluster does interpret this as a correctly running database.

3

SAP HANA database is up and in status info. The cluster does interpret this as a correctly running database.

2

SAP HANA database is up and in status warning. The cluster does interpret this as a correctly running database.

1

SAP HANA database is down. If the database should be up and is not down by intention, this could trigger a takeover.

0

Internal Script Error – to be ignored.

11.3 Maintenance

To receive updates for the operating system or the SUSE Linux Enterprise High Availability Extension, it is recommended to register your systems to either a local SUSE Manager, to the Subscription Management Tool (SMT), or remotely with SUSE Customer Center. For more information, visit the respective Web pages: https://www.suse.com/products/suse-manager/ https://documentation.suse.com/sles/12-SP4/html/SLES-all/smt-client.html https://scc.suse.com/docs/help Examples for maintenance tasks are also given in manual page SAPHanaSR_maintenance_examples(7).

11.3.1 Updating the OS and Cluster

For an update of SUSE Linux Enterprise Server for SAP Applications packages including cluster software, follow the rolling update procedure defined in the product documentation of the SUSE Linux Enterprise High Availability Extension Administration Guide, chapter Upgrading Your Cluster and Updating Software Packages at https://documentation.suse.com/sle-ha/12-SP4/html/SLE-HA-all/cha-ha-migration.html

11.3.2 Updating SAP HANA - Seamless SAP HANA Maintenance

For updating SAP HANA database systems in system replication, you need to follow the defined SAP processes. This section describes the steps required before and after the update procedure to get the system replication automated again.

SUSE has optimized the SAP HANA maintenance process in the cluster. The improved procedure only sets the multi-state resource to maintenance and keeps the rest of the cluster (SAPHanaTopology clones and IPaddr2 vIP resource) still active. Using the updated procedure allows a seamless SAP HANA maintenance in the cluster, as the virtual IP address can automatically follow the running primary.

Prepare the cluster not to react on the maintenance work to be done on the SAP HANA database systems. Set the multi-state resource to maintenance.

Example 45: Main SAP HANA Update procedure
Pre-Update Tasks

For the multi-state-resource set the maintenance mode as follows:

crm resource maintenance <multi-state-resource>

The <multi-state-resource> in the guide at hand is msl_SAPHana_HA1_HDB10.

Update

Process the SAP Update for both SAP HANA database systems. This procedure is described by SAP.

Post-Update Tasks

Expect the primary/secondary roles to be exchanged after the maintenance. Therefore, tell the cluster to forget about these states and to reprobe the updated SAP HANA database systems.

crm resource refresh <multi-state-resource>

After the SAP HANA update is complete on both sites, tell the cluster about the end of the maintenance process. This allows the cluster to actively control and monitor the SAP again.

crm resource maintenance <multi-state-resource> off

11.3.3 Migrating an SAP HANA Primary

In the following procedures we assume the primary runs on node1 and the secondary on node2. The goal is to "exchange" the roles of the nodes: the primary should then run on node2 and the secondary should run on node1.

There are different methods to get the exchange of the roles done. The following procedure shows how to tell the cluster to "accept" a role change via native HANA commands.

Example 46: Migrating an SAP HANA primary using SAP Toolset
Pre-Migration Tasks

Set the multi-state resource to maintenance. This can be done on any cluster node.

crm resource maintenance <multi-state-resource-name>
Manual Takeover Process
  • Stop the primary SAP HANA database system. Enter the command in our example on node1 as user <sid>adm.

    HDB stop
  • Before proceeding, make sure the primary HANA database is stopped.

  • Start the takeover process on the secondary SAP HANA database system. Enter the command in our example on node2 as user <sid>adm.

    hdbnsutil -sr_takeover
  • Register the former primary to become the new secondary. Enter the command in our example on node1 as user <sid>adm.

    hdbnsutil -sr_register --remoteHost=suse02 --remoteInstance=10 \
     --replicationMode=sync --name=WDF \
     --operationMode=logreplay
  • Start the new secondary SAP HANA database system. Enter the command in our example on node1 as user <sid>adm.

    HDB start
Post-Migration Tasks
  • Wait some time until SAPHanaSR-showAttr shows both SAP HANA database systems to be up again (field roles must start with the digit 4). The new secondary should have role "S" (for secondary).

  • Tell the cluster to forget about the former multi-state roles and to re-monitor the failed master. The command can be submitted on any cluster node as user root.

    crm resource refresh <multi-state-resource-name>
  • Set the multi-state resource to the status managed again. The command can be submitted on any cluster node as user root.

    crm resource maintenance <multi-state-resource-name> off

The following paragraphs explain how to use the cluster to partially automate the migration. For the described attribute query using SAPHanaSR-showAttr and SAPHanaSR-filter you need at least SAPHanaSR with package version 0.153.

Example 47: Moving an SAP HANA primary using the Cluster Toolset
  • Create a "move away" from this node rule by using the force option.

    crm resource move <multi-state-resource-name> force

    Because of the "move away" (force) rule, the cluster will stop the current primary. After that, run a promote on the secondary site if the system replication was in sync before. You should not migrate the primary if the status of the system replication is not in sync (SFAIL).

    Important
    Important

    Migration without the force option will cause a takeover without the former primary to be stopped. Only the migration with force option is supported.

    Note
    Note

    The crm resource command move was previously named migrate. The migrate command is still valid but already known as obsolete.

  • Wait until the secondary has completely taken over to be the new primary role. You see this using the command line tool SAPHanaSR-showAttr. Now check for the attributes "roles" for the new primary. It must start with "4:P".

    suse01:~ # SAPHanaSR-showAttr --format=script | \
       SAPHanaSR-filter --search='roles'
    Mon Nov 11 20:38:50 2019; Hosts/suse01/roles=1:P:master1::worker:
    Mon Nov 11 20:38:50 2019; Hosts/suse02/roles=4:P:master1:master:worker:master
  • If you have set up the parameter value AUTOMATED_REGISTER="true", you can skip this step. In other cases you now need to register the old primary. Enter the command in our example on node1 as user <sid>adm.

    hdbnsutil -sr_register --remoteHost=suse02 --remoteInstance=10 \
        --replicationMode=sync --operationMode=logreplay \
        --name=WDF
  • Clear the ban rules of the resource to allow the cluster to start the new secondary.

    # crm resource clear <multi-state-resource-name>
    Note
    Note

    The crm resource command clear was previously named unmigrate. The unmigrate command is still valid but already known as obsolete.

  • Wait until the new secondary has started. You see this using the command line tool SAPHanaSR-showAttr and check for the attributes "roles" for the new primary. It must start with "4:S".

    suse01:~ # SAPHanaSR-showAttr --format=script | \
       SAPHanaSR-filter --search='roles'
    Mon Nov 11 20:38:50 2019; Hosts/suse01/roles=4:S:master1::worker:
    Mon Nov 11 20:38:50 2019; Hosts/suse02/roles=4:P:master1:master:worker:master
  • You might want to revert the SAP HANA roles back soon, to get the non-replicated database also up and running again.

11.3.4 Revert to Original SAP HANA Roles After Takeover to Secondary Site

Example 48: Revert SAP HANA Roles back after Failure on suse01
  • Register the former primary as new secondary as user <sid>adm.

    suse01 > hdbnsutil -sr_register --name=WDF \
     	--remoteHost=suse02 --remoteInstance=10 \
    	--replicationMode=syncmem --operationMode=logreplay
  • Clean up the failcount for SAP HANA resource as user root.

    # crm configure show rsc_SAPHana_HA1_HDB10 | grep AUTOMATED_REGISTER
    # crm resource cleanup msl_SAPHana_HA1_HDB10 suse01
  • Recover the SAP HANA global.ini back to initial state, as user <sid>adm.

    suse02 > cdcoc
    suse02 > cp global.ini global.ini.bak
    suse02 > vi global.ini
    [memorymanager]
    global_allocation_limit = <size_in_mb_for_secondary_hana>
    ...
    [system_replication]
    preload_column_tables = false
  • Move the SAP HANA Primary back to suse01, as root user.

    # crm resource move <multi-state-resource-name> force
  • Wait until the cluster has finished the transition and is idle. Then remove the migration constraint from CIB.

    # crm resource clear <multi-state-resource-name>

11.4 Support

There are two channels available for opening support requests. For issues which might also need SAP to investigate, the preferred method is to open an SAP ticket on support queue BC-OP-LNX-SUSE. See SAP note 1056161; find the link in Section 12.5, “SAP Notes”.

The other channel is to use the SUSE support only. SUSE customer center (SCC) is the central access point for managing support entitlements and for opening support requests. It is available at https://scc.suse.com/login.

More information on how to access support can be foud at https://www.suse.com/support/ and https://www.suse.com/support/faq/.

The SUSE Linux Enterprise Server for SAP Applications product documentation explains how to collect information usually needed during a support request: https://documentation.suse.com/sles/12-SP4/html/SLES-all/cha-adm-support.html.

See also manual pages crm_report(8), supportconfg(8), cs_show_hana_info(8), ha_related_suse_tids(7).

In addition, there are SUSE support Technical Information Documents (TIDs) available, for example:

  • Diagnostic Data Collection Master TID (7024037)

  • Indepth HANA Cluster Debug Data Collection (PACEMAKER, SAP) (7022702)

  • SLES for SAP - How To Engage SAP and SUSE to address Product Issues (7021182)

The SUSE support knowledgebase containing the TIDs is available at https://www.suse.com/support/kb/.

12 Useful Links, Manuals, and SAP Notes

12.1 SUSE Best Practices and More

Best Practices for SAP on SUSE Linux Enterprise

https://documentation.suse.com/sbp/all/

Blog series of articles under the tag #towardsZeroDowntime

https://www.suse.com/c/tag/towardszerodowntime/

Blog article "SAP HANA Cost-optimized – An alternative Route is available"

https://suse.com/c/sap-hana-cost-optimized-an-alternative-route-is-available/

Blog article "Fail-Safe Operation of SAP HANA®: SUSE Extends Its High Availability Solution"

http://scn.sap.com/community/hana-in-memory/blog/2014/04/04/fail-safe-operation-of-sap-hana-suse-extends-its-high-availability-solution

12.2 SUSE Product Documentation

SUSE product manuals and documentation

https://documentation.suse.com/

Current online documentation for SUSE Linux Enterprise Server for SAP Applications 12

https://documentation.suse.com/sles-sap/12-SP4/

Current online documentation for SUSE Linux Enterprise High Availability Extension 12

https://documentation.suse.com/sle-ha/12-SP4/

System Analysis and Tuning Guide for SUSE Linux Enterprise Server 12

https://documentation.suse.com/sles/12-SP4/html/SLES-all/book-sle-tuning.html

Storage Administration Guide for SUSE Linux Enterprise Server 12

https://documentation.suse.com/sles/12-SP4/single-html/SLES-storage/#stor-admin

Release notes

https://www.suse.com/releasenotes

TID Estimate correct multipath timeout

http://www.suse.com/support/kb/doc.php?id=7008216

TID How to load the correct watchdog kernel module

http://www.suse.com/support/kb/doc.php?id=7016880

TID Addressing file system performance issues on NUMA machines

http://www.suse.com/support/kb/doc.php?id=7008919

TID Overcommit Memory in SLES

https://www.suse.com/support/kb/doc.php?id=7002775

SUSE Linux Enterprise Tech Specs

https://www.suse.com/products/server/#tech-specs/

XFS file system

https://www.suse.com/communities/conversations/xfs-the-file-system-of-choice/

SUSE YES certified hardware database

https://www.suse.com/yessearch/

12.3 Manual Pages

crm

crm.8

crm_simulate

crm_simulate.8

cs_clusterstate

cs_clusterstate.8

ocf_suse_SAPHana

ocf_suse_SAPHana.7

ocf_suse_SAPHanaTopology

ocf_suse_SAPHanaTopology.7

sbd

sbd.8

stonith_sbd

stonith_sbd.7

SAPHanaSR

SAPHanaSR.7

SAPHanaSR-showAttr

SAPHanaSR-showAttr.8

SAPHanaSR-replay-archive

SAPHanaSR-replay-archive.8

SAPHanaSR_maintenance_examples

SAPHanaSR_maintenance_examples.8

12.5 SAP Notes

1056161 - SUSE Priority Support for SAP applications

https://launchpad.support.sap.com/#/notes/1056161

1984787 - SUSE LINUX Enterprise Server 12: Installation notes

https://launchpad.support.sap.com/#/notes/1984787

2205917 - SAP HANA DB: Recommended OS settings for SLES 12 / SLES for SAP Applications 12

https://launchpad.support.sap.com/#/notes/2205917

1876398 - Network configuration for System Replication in HANA SP6

https://launchpad.support.sap.com/#/notes/1876398

611361 - Hostnames of SAP servers

https://launchpad.support.sap.com/#/notes/611361

1275776 - Preparing SLES for Sap Environments

https://launchpad.support.sap.com/#/notes/1275776

1514967 - SAP HANA: Central Note

https://launchpad.support.sap.com/#/notes/1514967

1523337 - SAP In-Memory Database 1.0: Central Note

https://launchpad.support.sap.com/#/notes/1523337

2380229 - SAP HANA Platform 2.0 - Central Note

https://launchpad.support.sap.com/#/notes/2380229

1501701 - Single Computing Unit Performance and Sizing

https://launchpad.support.sap.com/#/notes/1501701

1944799 - SAP HANA Guidelines for SLES Operating System Installation

https://launchpad.support.sap.com/#/notes/1944799

1890444 - Slow HANA system due to CPU power save mode

https://launchpad.support.sap.com/#/notes/1890444

1888072 - SAP HANA DB: Indexserver crash in strcmp sse42

https://launchpad.support.sap.com/#/notes/1888072

1846872 - "No space left on device" error reported from HANA

https://launchpad.support.sap.com/#/notes/1846872

13 Examples

13.1 Example ha-cluster-init Configuration

suse01:~ # ha-cluster-init -u
  Generating SSH key
  Configuring csync2
  Generating csync2 shared key (this may take a while)...done
  csync2 checking files...done

Configure Corosync (unicast):
  This will configure the cluster messaging layer.  You will need
  to specify a network address over which to communicate (default
  is eth0's network, but you can use the network address of any
  active interface).

  Address for ring0 [192.168.1.11]
  Port for ring0 [5405]

Configure SBD:
  If you have shared storage, for example a SAN or iSCSI target,
  you can use it avoid split-brain scenarios by configuring SBD.
  This requires a 1 MB partition, accessible to all nodes in the
  cluster.  The device path must be persistent and consistent
  across all nodes in the cluster, so /dev/disk/by-id/* devices
  are a good choice.  Note that all data on the partition you
  specify here will be destroyed.

Do you wish to use SBD (y/n)? y
  Path to storage device (e.g. /dev/disk/by-id/...), or "none" []/dev/disk/by-id/SBDA
All data on /dev/disk/by-id/SBDA will be destroyed!
Are you sure you wish to use this device (y/n)? y
  Initializing SBD......done
  Hawk cluster interface is now running. To see cluster status, open:
    https://192.168.1.11:7630/
  Log in with username 'hacluster', password 'linux'
You should change the hacluster password to something more secure!
  Waiting for cluster........done
  Loading initial cluster configuration

Configure Administration IP Address:
  Optionally configure an administration virtual IP
  address. The purpose of this IP address is to
  provide a single IP that can be used to interact
  with the cluster, rather than using the IP address
  of any specific cluster node.

Do you wish to configure a virtual IP address (y/n)? n
  Done (log saved to /var/log/ha-cluster-bootstrap.log)

13.2 Example Cluster Configuration

The following example shows a complete crm configuration for a two-node cluster (suse01, suse02) and a replicated SAP HANA database with SID HA1 and instance number 10. The standalone database has SID QAS and instance number 20.The virtual IP address in the example is 192.168.1.20

node suse01
node suse02

primitive rsc_SAPHanaTopology_HA1_HDB10 ocf:suse:SAPHanaTopology \
        op monitor interval=10 timeout=300 \
        op start interval=0 timeout=300 \
        op stop interval=0 timeout=300 \
        params SID=HA1 InstanceNumber=10

primitive rsc_SAPHana_HA1_HDB10 ocf:suse:SAPHana \
        op monitor interval=61 role=Slave timeout=700 \
        op start interval=0 timeout=3600 \
        op stop interval=0 timeout=3600 \
        op promote interval=0 timeout=3600 \
        op monitor interval=60 role=Master timeout=700 \
        params SID=HA1 InstanceNumber=10 PREFER_SITE_TAKEOVER=false \
               DUPLICATE_PRIMARY_TIMEOUT=7200 AUTOMATED_REGISTER=false

primitive rsc_SAP_QAS_HDB20 ocf:heartbeat:SAPInstance \
     params InstanceName="QAS_HDB20_sapqasdb" \
        MONITOR_SERVICES="hdbindexserver|hdbnameserver" \
        START_PROFILE="/usr/sap/QAS/SYS/profile/QAS_HDB20_sapqasdb" \
     op start interval="0" timeout="600" \
     op monitor interval="120" timeout="700" \
     op stop interval="0" timeout="300" \
     meta priority="100"

primitive rsc_ip_HA1_HDB10 ocf:heartbeat:IPaddr2 \
        op monitor interval=10 timeout=20 \
        params ip="192.168.1.20"

primitive stonith-sbd stonith:external/sbd \
        params pcmk_delay_max=30

ms msl_SAPHana_HA1_HDB10 rsc_SAPHana_HA1_HDB10 \
        meta clone-max=2 clone-node-max=1 interleave=true

clone cln_SAPHanaTopology_HA1_HDB10 rsc_SAPHanaTopology_HA1_HDB10 \
        meta clone-node-max=1 interleave=true

location loc_QAS_never_on_suse01 rsc_SAP_HA1_HDB10 -inf: suse01

colocation col_QAS_never_with_HA1ip -inf: rsc_SAP_QAS_HDB20:Started \
  rsc_ip_HA1_HDB10

order ord_QASstop_before_HA1-promote Mandatory: rsc_SAP_QAS_HDB20:stop \
  msl_SAPHana_HA1_HDB10:promote

colocation col_saphana_ip_HA1_HDB10 2000: \
        rsc_ip_HA1_HDB10:Started msl_SAPHana_HA1_HDB10:Master

order ord_SAPHana_HA1_HDB10 Optional: \
        cln_SAPHanaTopology_HA1_HDB10 msl_SAPHana_HA1_HDB10

property cib-bootstrap-options: \
        cluster-infrastructure=corosync \
        stonith-enabled=true \
        stonith-action=reboot \
        stonith-timeout=150s

rsc_defaults rsc-options: \
        resource-stickiness=1000 \
        migration-threshold=3

op_defaults op-options \
        timeout=600 \
        record-pending=true

13.3 Example for /etc/corosync/corosync.conf

The following file shows a typical corosync configuration with one ring. Review the SUSE product documentation about details and about additional rings.

# Read the corosync.conf.5 manual page
totem {
        version: 2
        secauth: on
        crypto_hash: sha1
        crypto_cipher: aes256
        cluster_name: suse-ha
        clear_node_high_bit: yes
        token: 5000
        token_retransmits_before_loss_const: 10
        join: 60
        consensus: 6000
        max_messages: 20
        interface {
                ringnumber: 0
                mcastport: 5405
                ttl: 1
        }

        transport: udpu
}

logging {
        fileline: off
        to_stderr: no
        to_logfile: no
        logfile: /var/log/cluster/corosync.log
        to_syslog: yes
        debug: off
        timestamp: on
        logger_subsys {
                subsys: QUORUM
                debug: off
        }

}

nodelist {
        node {
                ring0_addr: 192.168.1.11
                nodeid: 1
        }

        node {
                ring0_addr: 192.168.1.12
                nodeid: 2
        }

}

quorum {

        # Enable and configure quorum subsystem (default: off)
        # see also corosync.conf.5 and votequorum.5
        provider: corosync_votequorum
        expected_votes: 2
        two_node: 1
}

13.4 Examples for Alternate STONITH Methods

13.4.1 Example for Deterministic SBD STONITH

These SBD resources make sure that node suse01 will win in case of split-brain.

primitive rsc_sbd_suse01 stonith:external/sbd \
    params pcmk_host_list=suse02 pcmk_delay_base=0

primitive rsc_sbd_suse02 stonith:external/sbd \
    params pcmk_host_list=suse01 pcmk_delay_base=30

13.4.2 Example for the IPMI STONITH Method

primitive rsc_suse01_stonith stonith:external/ipmi \
    params hostname="suse01" ipaddr="192.168.1.101" userid="stonith" \
    passwd="k1llm3" interface="lanplus" \
    op monitor interval="1800" timeout="30"
    ...
primitive rsc_suse02_stonith stonith:external/ipmi \
    params hostname="suse02" ipaddr="192.168.1.102" userid="stonith" \
    passwd="k1llm3" interface="lanplus" \
    op monitor interval="1800" timeout="30"
    ...
location loc_suse01_stonith rsc_suse01_stonith -inf: suse01
location loc_suse02_stonith rsc_suse02_stonith -inf: suse02

13.4.3 srCostOptMemConfig

Note
Note

This hook is given "as-is". It must be installed at node 2 as /hana/shared/srHook/srCostOptMemConfig.py to undo the changes to global_allocation_limit and preload_column_tables in case of a takeover.

#!/usr/bin/env python2

"""
Sample for a HA/DR hook provider for method srPostTakeover().
When using your own code in here, please copy this file to location on /hana/shared
outside the HANA installation.

To configure your own changed version of this file, please add to your global.ini lines similar to this:

[ha_dr_provider_<className>]
provider = <className>
path = /hana/shared/srHook/
execution_order = 2

For all hooks, 0 must be returned in case of success.
Set the following variables:
* dbinst Instance Number [e.g. 00 - 99 ]
* dbuser Username [ e.g. SYSTEM ]
* dbpwd
* user password [ e.g. SLES4sap ]
* dbport port where db listens for SQL connctions [e.g 30013 or 30015]
"""
#
# parameter section
#
dbuser="SYSTEM"
dbpwd="<yourPassword1234>"
dbinst="00"
dbport="30013"
#
# prepared SQL statements to remove memory allocation limit
#    and pre-load of column tables
#
stmnt1 = "ALTER SYSTEM ALTER CONFIGURATION ('global.ini','SYSTEM') UNSET ('memorymanager','global_allocation_limit') WITH RECONFIGURE"
stmnt2 = "ALTER SYSTEM ALTER CONFIGURATION ('global.ini','SYSTEM') UNSET ('system_replication','preload_column_tables') WITH RECONFIGURE"
#
# loading classes and libraries
#
import os, time, dbapi
from hdb_ha_dr.client import HADRBase, Helper
#
# class definition srCostOptMemConfig
#
class srCostOptMemConfig(HADRBase):
  def __init__(self, *args, **kwargs):
       # delegate construction to base class
       super(srCostOptMemConfig, self).__init__(*args, **kwargs)

  def about(self):
      return {"provider_company" : "<customer>",
              "provider_name" : "srCostOptMemConfig", # provider name = class name
              "provider_description" : "Replication takeover script to set parameters to default.",
              "provider_version" : "1.0"}

  def postTakeover(self, rc, **kwargs):
      """Post takeover hook."""
      self.tracer.info("%s.postTakeover method called with rc=%s" % (self.__class__.__name__, rc))
      if rc == 0:
         # normal takeover succeeded
         conn = dbapi.connect('localhost',dbport,dbuser,dbpwd)
         cursor = conn.cursor()
         cursor.execute(stmnt1)
         cursor.execute(stmnt2)
         return 0
      elif rc == 1:
          # waiting for force takeover
          conn = dbapi.connect('localhost',dbport,dbuser,dbpwd)
          cursor = conn.cursor()
          cursor.execute(stmnt1)
          cursor.execute(stmnt2)
          return 0
      elif rc == 2:
          # error, something went wrong
          return 0

15 GNU Free Documentation License

Copyright © 2000, 2001, 2002 Free Software Foundation, Inc. 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed.

0. PREAMBLE

The purpose of this License is to make a manual, textbook, or other functional and useful document "free" in the sense of freedom: to assure everyone the effective freedom to copy and redistribute it, with or without modifying it, either commercially or noncommercially. Secondarily, this License preserves for the author and publisher a way to get credit for their work, while not being considered responsible for modifications made by others.

This License is a kind of "copyleft", which means that derivative works of the document must themselves be free in the same sense. It complements the GNU General Public License, which is a copyleft license designed for free software.

We have designed this License in order to use it for manuals for free software, because free software needs free documentation: a free program should come with manuals providing the same freedoms that the software does. But this License is not limited to software manuals; it can be used for any textual work, regardless of subject matter or whether it is published as a printed book. We recommend this License principally for works whose purpose is instruction or reference.

1. APPLICABILITY AND DEFINITIONS

This License applies to any manual or other work, in any medium, that contains a notice placed by the copyright holder saying it can be distributed under the terms of this License. Such a notice grants a world-wide, royalty-free license, unlimited in duration, to use that work under the conditions stated herein. The "Document", below, refers to any such manual or work. Any member of the public is a licensee, and is addressed as "you". You accept the license if you copy, modify or distribute the work in a way requiring permission under copyright law.

A "Modified Version" of the Document means any work containing the Document or a portion of it, either copied verbatim, or with modifications and/or translated into another language.

A "Secondary Section" is a named appendix or a front-matter section of the Document that deals exclusively with the relationship of the publishers or authors of the Document to the Document’s overall subject (or to related matters) and contains nothing that could fall directly within that overall subject. (Thus, if the Document is in part a textbook of mathematics, a Secondary Section may not explain any mathematics.) The relationship could be a matter of historical connection with the subject or with related matters, or of legal, commercial, philosophical, ethical or political position regarding them.

The "Invariant Sections" are certain Secondary Sections whose titles are designated, as being those of Invariant Sections, in the notice that says that the Document is released under this License. If a section does not fit the above definition of Secondary then it is not allowed to be designated as Invariant. The Document may contain zero Invariant Sections. If the Document does not identify any Invariant Sections then there are none.

The "Cover Texts" are certain short passages of text that are listed, as Front-Cover Texts or Back-Cover Texts, in the notice that says that the Document is released under this License. A Front-Cover Text may be at most 5 words, and a Back-Cover Text may be at most 25 words.

A "Transparent" copy of the Document means a machine-readable copy, represented in a format whose specification is available to the general public, that is suitable for revising the document straightforwardly with generic text editors or (for images composed of pixels) generic paint programs or (for drawings) some widely available drawing editor, and that is suitable for input to text formatters or for automatic translation to a variety of formats suitable for input to text formatters. A copy made in an otherwise Transparent file format whose markup, or absence of markup, has been arranged to thwart or discourage subsequent modification by readers is not Transparent. An image format is not Transparent if used for any substantial amount of text. A copy that is not "Transparent" is called "Opaque".

Examples of suitable formats for Transparent copies include plain ASCII without markup, Texinfo input format, LaTeX input format, SGML or XML using a publicly available DTD, and standard-conforming simple HTML, PostScript or PDF designed for human modification. Examples of transparent image formats include PNG, XCF and JPG. Opaque formats include proprietary formats that can be read and edited only by proprietary word processors, SGML or XML for which the DTD and/or processing tools are not generally available, and the machine-generated HTML, PostScript or PDF produced by some word processors for output purposes only.

The "Title Page" means, for a printed book, the title page itself, plus such following pages as are needed to hold, legibly, the material this License requires to appear in the title page. For works in formats which do not have any title page as such, "Title Page" means the text near the most prominent appearance of the work’s title, preceding the beginning of the body of the text.

A section "Entitled XYZ" means a named subunit of the Document whose title either is precisely XYZ or contains XYZ in parentheses following text that translates XYZ in another language. (Here XYZ stands for a specific section name mentioned below, such as "Acknowledgements", "Dedications", "Endorsements", or "History".) To "Preserve the Title" of such a section when you modify the Document means that it remains a section "Entitled XYZ" according to this definition.

The Document may include Warranty Disclaimers next to the notice which states that this License applies to the Document. These Warranty Disclaimers are considered to be included by reference in this License, but only as regards disclaiming warranties: any other implication that these Warranty Disclaimers may have is void and has no effect on the meaning of this License.

2. VERBATIM COPYING

You may copy and distribute the Document in any medium, either commercially or noncommercially, provided that this License, the copyright notices, and the license notice saying this License applies to the Document are reproduced in all copies, and that you add no other conditions whatsoever to those of this License. You may not use technical measures to obstruct or control the reading or further copying of the copies you make or distribute. However, you may accept compensation in exchange for copies. If you distribute a large enough number of copies you must also follow the conditions in section 3.

You may also lend copies, under the same conditions stated above, and you may publicly display copies.

3. COPYING IN QUANTITY

If you publish printed copies (or copies in media that commonly have printed covers) of the Document, numbering more than 100, and the Document’s license notice requires Cover Texts, you must enclose the copies in covers that carry, clearly and legibly, all these Cover Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on the back cover. Both covers must also clearly and legibly identify you as the publisher of these copies. The front cover must present the full title with all words of the title equally prominent and visible. You may add other material on the covers in addition. Copying with changes limited to the covers, as long as they preserve the title of the Document and satisfy these conditions, can be treated as verbatim copying in other respects.

If the required texts for either cover are too voluminous to fit legibly, you should put the first ones listed (as many as fit reasonably) on the actual cover, and continue the rest onto adjacent pages.

If you publish or distribute Opaque copies of the Document numbering more than 100, you must either include a machine-readable Transparent copy along with each Opaque copy, or state in or with each Opaque copy a computer-network location from which the general network-using public has access to download using public-standard network protocols a complete Transparent copy of the Document, free of added material. If you use the latter option, you must take reasonably prudent steps, when you begin distribution of Opaque copies in quantity, to ensure that this Transparent copy will remain thus accessible at the stated location until at least one year after the last time you distribute an Opaque copy (directly or through your agents or retailers) of that edition to the public.

It is requested, but not required, that you contact the authors of the Document well before redistributing any large number of copies, to give them a chance to provide you with an updated version of the Document.

4. MODIFICATIONS

You may copy and distribute a Modified Version of the Document under the conditions of sections 2 and 3 above, provided that you release the Modified Version under precisely this License, with the Modified Version filling the role of the Document, thus licensing distribution and modification of the Modified Version to whoever possesses a copy of it. In addition, you must do these things in the Modified Version:

  1. Use in the Title Page (and on the covers, if any) a title distinct from that of the Document, and from those of previous versions (which should, if there were any, be listed in the History section of the Document). You may use the same title as a previous version if the original publisher of that version gives permission.

  2. List on the Title Page, as authors, one or more persons or entities responsible for authorship of the modifications in the Modified Version, together with at least five of the principal authors of the Document (all of its principal authors, if it has fewer than five), unless they release you from this requirement.

  3. State on the Title page the name of the publisher of the Modified Version, as the publisher.

  4. Preserve all the copyright notices of the Document.

  5. Add an appropriate copyright notice for your modifications adjacent to the other copyright notices.

  6. Include, immediately after the copyright notices, a license notice giving the public permission to use the Modified Version under the terms of this License, in the form shown in the Addendum below.

  7. Preserve in that license notice the full lists of Invariant Sections and required Cover Texts given in the Document’s license notice.

  8. Include an unaltered copy of this License.

  9. Preserve the section Entitled "History", Preserve its Title, and add to it an item stating at least the title, year, new authors, and publisher of the Modified Version as given on the Title Page. If there is no section Entitled "History" in the Document, create one stating the title, year, authors, and publisher of the Document as given on its Title Page, then add an item describing the Modified Version as stated in the previous sentence.

  10. Preserve the network location, if any, given in the Document for public access to a Transparent copy of the Document, and likewise the network locations given in the Document for previous versions it was based on. These may be placed in the "History" section. You may omit a network location for a work that was published at least four years before the Document itself, or if the original publisher of the version it refers to gives permission.

  11. For any section Entitled "Acknowledgements" or "Dedications", Preserve the Title of the section, and preserve in the section all the substance and tone of each of the contributor acknowledgements and/or dedications given therein.

  12. Preserve all the Invariant Sections of the Document, unaltered in their text and in their titles. Section numbers or the equivalent are not considered part of the section titles.

  13. Delete any section Entitled "Endorsements". Such a section may not be included in the Modified Version.

  14. Do not retitle any existing section to be Entitled "Endorsements" or to conflict in title with any Invariant Section.

  15. Preserve any Warranty Disclaimers.

If the Modified Version includes new front-matter sections or appendices that qualify as Secondary Sections and contain no material copied from the Document, you may at your option designate some or all of these sections as invariant. To do this, add their titles to the list of Invariant Sections in the Modified Version’s license notice. These titles must be distinct from any other section titles.

You may add a section Entitled "Endorsements", provided it contains nothing but endorsements of your Modified Version by various parties—​for example, statements of peer review or that the text has been approved by an organization as the authoritative definition of a standard.

You may add a passage of up to five words as a Front-Cover Text, and a passage of up to 25 words as a Back-Cover Text, to the end of the list of Cover Texts in the Modified Version. Only one passage of Front-Cover Text and one of Back-Cover Text may be added by (or through arrangements made by) any one entity. If the Document already includes a cover text for the same cover, previously added by you or by arrangement made by the same entity you are acting on behalf of, you may not add another; but you may replace the old one, on explicit permission from the previous publisher that added the old one.

The author(s) and publisher(s) of the Document do not by this License give permission to use their names for publicity for or to assert or imply endorsement of any Modified Version.

5. COMBINING DOCUMENTS

You may combine the Document with other documents released under this License, under the terms defined in section 4 above for modified versions, provided that you include in the combination all of the Invariant Sections of all of the original documents, unmodified, and list them all as Invariant Sections of your combined work in its license notice, and that you preserve all their Warranty Disclaimers.

The combined work need only contain one copy of this License, and multiple identical Invariant Sections may be replaced with a single copy. If there are multiple Invariant Sections with the same name but different contents, make the title of each such section unique by adding at the end of it, in parentheses, the name of the original author or publisher of that section if known, or else a unique number. Make the same adjustment to the section titles in the list of Invariant Sections in the license notice of the combined work.

In the combination, you must combine any sections Entitled "History" in the various original documents, forming one section Entitled "History"; likewise combine any sections Entitled "Acknowledgements", and any sections Entitled "Dedications". You must delete all sections Entitled "Endorsements".

6. COLLECTIONS OF DOCUMENTS

You may make a collection consisting of the Document and other documents released under this License, and replace the individual copies of this License in the various documents with a single copy that is included in the collection, provided that you follow the rules of this License for verbatim copying of each of the documents in all other respects.

You may extract a single document from such a collection, and distribute it individually under this License, provided you insert a copy of this License into the extracted document, and follow this License in all other respects regarding verbatim copying of that document.

7. AGGREGATION WITH INDEPENDENT WORKS

A compilation of the Document or its derivatives with other separate and independent documents or works, in or on a volume of a storage or distribution medium, is called an "aggregate" if the copyright resulting from the compilation is not used to limit the legal rights of the compilation’s users beyond what the individual works permit. When the Document is included in an aggregate, this License does not apply to the other works in the aggregate which are not themselves derivative works of the Document.

If the Cover Text requirement of section 3 is applicable to these copies of the Document, then if the Document is less than one half of the entire aggregate, the Document’s Cover Texts may be placed on covers that bracket the Document within the aggregate, or the electronic equivalent of covers if the Document is in electronic form. Otherwise they must appear on printed covers that bracket the whole aggregate.

8. TRANSLATION

Translation is considered a kind of modification, so you may distribute translations of the Document under the terms of section 4. Replacing Invariant Sections with translations requires special permission from their copyright holders, but you may include translations of some or all Invariant Sections in addition to the original versions of these Invariant Sections. You may include a translation of this License, and all the license notices in the Document, and any Warranty Disclaimers, provided that you also include the original English version of this License and the original versions of those notices and disclaimers. In case of a disagreement between the translation and the original version of this License or a notice or disclaimer, the original version will prevail.

If a section in the Document is Entitled "Acknowledgements", "Dedications", or "History", the requirement (section 4) to Preserve its Title (section 1) will typically require changing the actual title.

9. TERMINATION

You may not copy, modify, sublicense, or distribute the Document except as expressly provided for under this License. Any other attempt to copy, modify, sublicense or distribute the Document is void, and will automatically terminate your rights under this License. However, parties who have received copies, or rights, from you under this License will not have their licenses terminated so long as such parties remain in full compliance.

10. FUTURE REVISIONS OF THIS LICENSE

The Free Software Foundation may publish new, revised versions of the GNU Free Documentation License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. See http://www.gnu.org/copyleft/.

Each version of the License is given a distinguishing version number. If the Document specifies that a particular numbered version of this License "or any later version" applies to it, you have the option of following the terms and conditions either of that specified version or of any later version that has been published (not as a draft) by the Free Software Foundation. If the Document does not specify a version number of this License, you may choose any version ever published (not as a draft) by the Free Software Foundation.

ADDENDUM: How to use this License for your documents

Copyright (c) YEAR YOUR NAME.
   Permission is granted to copy, distribute and/or modify this document
   under the terms of the GNU Free Documentation License, Version 1.2
   or any later version published by the Free Software Foundation;
   with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
   A copy of the license is included in the section entitled “GNU
   Free Documentation License”.

If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts, replace the “ with…​Texts.” line with this:

with the Invariant Sections being LIST THEIR TITLES, with the
   Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST.

If you have Invariant Sections without Cover Texts, or some other combination of the three, merge those two alternatives to suit the situation.

If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software.

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