SAP HANA System Replication Scale-Out - Multi-Target Performance-Optimized Scenario #

This document describes how to set up SAP HANA scale-out multi-target system replication with a cluster installed on two sites (and a third site which acts as majority maker) based on SUSE Linux Enterprise Server for SAP Applications 15 SP4. Furthermore, it describes how to add an additional non-cluster site for a multi-target architecture. This concept can also be used with SUSE Linux Enterprise Server for SAP Applications 15 SP1 or newer.

For a better understanding and overview, the installation and setup is subdivided into seven steps.

Figure 1: Section 3, “Planning the installation” [OsSetup] [SAPHanaInst] [SAPHanaHsr] Section 7, “Integrating SAP HANA with the Linux cluster” Section 8, “Configuring the cluster and SAP HANA resources” Section 9, “Setup of a scale-out multi-target architecture” [Testing] #

 

First, we will set up a SUSE Linux Enterprise Server for SAP Applications cluster controlling two sites of SAP HANA scale-out in a system replication configuration. Next, we will set up a third site which is outside the SUSE Linux Enterprise High Availability Extension cluster but acts as additional SAP HANA target, forming a multi-target architecture.

Figure 2: Cluster with SAP HANA Multi-Target SR - performance optimized #

 

With SAPHanaSR-ScaleOut, various SAP HANA scale-out configurations are supported. Details on requirements and supported scenarios are given below.

In this guide we will cover a scale-out scenario without standby nodes, thus there is no host auto-failover. More details are explained at https://www.suse.com/c/sap-hana-scale-out-system-replication-for-large-erp-systems/ . The scenario where SAP HANA is configured for host auto-failover is explained at https://documentation.suse.com/sbp/all/html/SLES4SAP-hana-scaleOut-PerfOpt-15/index.html .

Note

For upgrading an existing SAP HANA scale-out system replication cluster from SAPHanaSR-ScaleOut version 0.160, consult manual page SAPHanaSR-manageAttr(8) and the blog article https://www.suse.com/c/sap-hana-scale-out-multi-target-upgrade/ .

Figure 3: Planning [OsSetup] [SAPHanaInst] [SAPHanaHsr] Section 7, “Integrating SAP HANA with the Linux cluster” Section 8, “Configuring the cluster and SAP HANA resources” Section 9, “Setup of a scale-out multi-target architecture” [Testing] #

 

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

What you need before you start:

3.1 Minimum lab requirements and prerequisites #

 

This section defines some minimum requirements to install SAP HANA scale-out multi-target in ERP style.

From SAP HANA perspective we have three sites with two nodes each. Each site has one NFS service providing three shares to the two nodes. The NFS services must not be stretched across sites. The /hana/shared/ needs to be shared across the two nodes. The /hana/data/ and /hana/log/ are on NFS and provided to both nodes, for simplicity. However, instead this two shares could be placed on the nodes locally, both file systems at each node.

Note

Refer to SAP HANA TDI documentation for allowed storage configuration and file systems.

From Linux cluster perspective we have three sites. Two of the cluster sites are hosting the workload. The third cluster site is for the majority maker node. HANA file systems and NFS shares are not managed by the Linux cluster.

Figure 4: Simplified NFS structure of an SAP HANA multi-target system replication cluster #

 

The SBD based fencing needs up to three block devices. They are shared across the three cluster sites and accessed by all five cluster nodes. One block device for SBD might be an iSCSI target placed at the cluster third site. The SBD block devices are backed by storage outside the cluster.

Figure 5: Simplified SBD structure of an SAP HANA multi-target system replication cluster #

 

Requirements with 2 SAP HANA instances per site (aka [ 2+0 ⇐ 2+0 ] → 2+0) plus the majority maker:

• 6 VMs with each 32 GB RAM, 50 GB disk space

• 1 VM with 2 GB RAM, 50 GB disk space

• 1 shared disk for SBD with 10 MB disk space

• 3 NFS pools (one per site) with a capacity of each 120 GB

• 1 additional IP address for takeover

• optional: 2nd additional IP address for active/read-enabled setup

Note

The minimum lab requirements mentioned here are no SAP sizing information. These data are provided only to rebuild the described cluster in a lab for test purposes. Even for such 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.

3.3 Scale-out scenario and HA resource agents #

 

To automate the failover of SAP HANA database and virtual IP resource between the first 2 sites in a scale-out multi-target setup, the High Availability Extension built into SUSE Linux Enterprise Server for SAP Applications is used. Two resource agents have been created to handle the scenario.

The first is the SAPHanaController resource agent (RA), which checks and manages the SAP HANA database instances. This RA is configured as a multi-state resource.

The master assumes responsibility for the active master name server of the SAP HANA database running in primary mode. All other instances are represented by the slave mode.

Figure 6: Cluster resource agents and multi-state status mapping #

 

The second resource agent is SAPHanaTopology. This RA has been created to make configuring the cluster as simple as possible. It runs on all nodes (except the majority maker) of a SUSE Linux Enterprise High Availability Extension 15 cluster. It gathers information about the statuses and configurations of the SAP HANA system replication. It is designed as a normal (stateless) clone resource.

With the current version of resource agents, SAP HANA system replication for scale-out is supported in the following scenarios or use cases:

Performance optimized, single container ([A => B])

In the performance optimized scenario an SAP HANA RDBMS on site "A" is synchronizing with an SAP HANA RDBMS on a second site "B". As the SAP HANA RDBMS on the second site is configured to preload the tables the takeover time is typically very short. See also the requirements section below for details.

Performance optimized, multi-tenancy also named MDC ([%A => %B])

Multi-tenancy is available for all of the supported scenarios and use cases in this document. This scenario is the default installation type for SAP HANA 2.0. The setup and configuration from a cluster point of view is the same for multi-tenancy and single containers. The one caveat is, that the tenants are managed all together by the Linux cluster. See also the requirements section below.

Multi-Tier Replication ([A => B] -> C)

A Multi-Tier system replication has an additional target, which must be connected to the secondary (chain topology). This is a special case of the Multi-Target replication. Because of the mandatory chain topology, the RA feature AUTOMATED_REGISTER=true is not possible with pure Multi-Tier replication. See also the requirements section below.

Multi-Target Replication ([A <= B] -> C)

This scenario and setup is described in this document. A Multi-Target system replication has an additional target, which is connected to either the secondary (chain topology) or to the primary (star topology). Multi-Target replication is possible since SAP HANA 2.0 SPS04. See also the requirements section below.

3.5 Important prerequisites #

 

Read the SAP Notes and papers first.

The SAPHanaSR-ScaleOut resource agent software package supports scale-out (multiple-box to multiple-box) system replication with the following configurations and parameters:

• The cluster must include a valid STONITH method. SBD disk-based is the recommended STONITH method.

• Both cluster controlled SAP HANA sites are either in the same network segment (layer 2) to allow an easy takeover of an IP Address, or you need a technique like overlay IP addresses in virtual private clouds.

• Technical users and groups, such as <sid>adm are defined locally in the Linux system.

• Name resolution of the cluster nodes and the virtual IP address should be done locally on all cluster nodes to not depend on DNS services (as it can fail, too).

• Time synchronization between the cluster nodes using reliable time services like NTP.

• All SAP HANA sites have the same SAP Identifier (SID) and instance number.

• The SAP HANA scale-out system must have only one active master name server per site. There are no configured master name server.

• For SAP HANA databases without additional master name server candidate, the package SAPHanaSR-ScaleOut version 0.180 or newer is needed.

• The SAP HANA scale-out system must have only one failover group.

• There is maximum one additional SAP HANA system replication connected from outside the Linux cluster. Thus two sites are managed by the Linux cluster, one site outside is recognized. For SAP HANA multi-tier and multi-target system replication, the package SAPHanaSR-ScaleOut version 0.180 or newer is needed.

• Only one SAP HANA SID is installed. Thus the performance optimized setup is supported. The cost optimized and MCOS scenarios are currently not supported.

• The saphostagent must be running. saphostagent is needed to translate between the system node names and SAP host names used during the installation of SAP HANA.

  • For SystemV style, the sapinit script needs to be active.

  • For systemd style, the services saphostagent and SAP<SID>_<INO> can stay enabled. The systemd enabled saphostagent and instance´s sapstartsrv is supported from SAPHanaSR-ScaleOut 0.181 onwards. Refer to the OS documentation for the systemd version. SAP HANA comes with native systemd integration as default starting with version 2.0 SPS07. Refer to SAP documentation for the SAP HANA version.

  • Combining systemd style hostagent with SystemV style instance is allowed. However, all nodes in one Linux cluster have to use the same style.

• All SAP HANA instances controlled by the cluster must not be activated via sapinit auto-start.

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

• The replication mode should be either 'sync' or 'syncmem'. 'async' is supported outside the Linux cluster.

• SAP HANA 2.0 SPS05 rev.059 and later provides Python 3 as well as the HA/DR provider hook method srConnectionChanged() with needed parameters for SAPHanaSrMultiTarget.py.

• SAP HANA 2.0 SPS05 or later provides the HA/DR provider hook method srServiceStateChanged() with needed parameters for susChkSrv.py.

• SAP HANA 2.0 SPS06 or later provides the HA/DR provider hook method preTakeover() with multi-target aware parameters and separate return code for Linux HA clusters.

• No other HA/DR provider hook script should be configured for the above mentioned methods. Hook scripts for other methods, provided in SAPHanaSR-ScaleOut, can be used in parallel, if not documented contradictingly.

• The Linux cluster needs to be up and running to allow HA/DR provider events being written into CIB attributes. The current HANA SR status might differ from CIB srHook attribute after Linux cluster maintenance.

• The user <sid>adm needs execution permission as user root for the command SAPHanaSR-hookHelper.

• For optimal automation, AUTOMATED_REGISTER="true" is recommended.

Important

As good starting configuration for projects, it is recommended to switch off the automated registration of a failed primary, therefor AUTOMATED_REGISTER="false" is the default.

In this case, you need to register a failed primary after a takeover manually. Use SAP tools like SAP HANA Cockpit or hdbnsutil. Make sure to use always the exact site names as already known to the cluster.

The two SAP HANA sites inside the Linux cluster can be configured to re-register the outer SAP HANA in case of takeover. For this a configuration item 'register_secondaries_on_takeover=true' needs to be added in the system_replication block of the global.ini file. See also manual page SAPHanaSrMultiTarget.py(7).

• You need at least SAPHanaSR-ScaleOut version 0.184, SUSE Linux Enterprise Server for SAP Applications 15 SP1 and SAP HANA 2.0 SPS 05 for all mentioned setups.

• The Linux cluster can be either freshly installed as described in this guide, or it can be upgraded as described in respective documentation. Not allowed is mixing old and new cluster attributes or hook scripts within one cluster.

• No manual actions must be performed on the SAP HANA database while it is controlled by the Linux cluster. All administrative actions need to be aligned with the cluster.

Find more details in the REQUIREMENTS section of manual pages SAPHanaSR-ScaleOut(7), ocf_suse_SAPHanaController(7), SAPHanaSrMultiTarget.py(7), SAPHanaSR-manageAttr(8), susChkSrv.py(7) and susTkOver.py(7).

Important

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

In this setup guide, NFS is used as storage for the SAP HANA database. This has been chosen for simplicity. However, any storage supported by SAP HANA and the SAP HANA storage API can be used. Refer to the SAP HANA TDI documentation for supported storage and follow the respective storage vendor’s configuration instructions.

This setup guide focuses on the scale-out multi-target setup.

If you need to implement a different scenario, it is strongly recommended to define a Proof-of-Concept (PoC) with SUSE. This PoC will focus on testing the existing solution in your scenario. The limitation of most of the above items is mostly because of testing limits.

Figure 7: Section 3, “Planning the installation” OsSetup [SAPHanaInst] [SAPHanaHsr] Section 7, “Integrating SAP HANA with the Linux cluster” Section 8, “Configuring the cluster and SAP HANA resources” Section 9, “Setup of a scale-out multi-target architecture” [Testing] #

 

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

In 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. Next, the automation with the cluster is set up and configured. Finally, the multi-target setup of the 3rd site is set up and configured.

4.1 Installing SUSE Linux Enterprise Server for SAP Applications #

 

Multiple installation guides are already existing, 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 system which is well prepared to deliver SAP HANA.

4.1.1 Installing the 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 (https://documentation.suse.com/sles/15-SP4/single-html/SLES-deployment/#book-deployment). In case of automated installations you can find further information in the AutoYaST Guide (https://documentation.suse.com/sles/15-SP4/single-html/SLES-autoyast/#book-autoyast). The major installation guide for SUSE Linux Enterprise Server for SAP Applications to fit all requirements for SAP HANA is described in the SAP notes:

• 2578899 SUSE Linux Enterprise Server 15: Installation Note and

• 2684254 SAP HANA DB: Recommended OS settings for SLES 15 / SLES for SAP Applications 15

4.1.2 Installing additional software #

 

SUSE delivers with SUSE Linux Enterprise Server for SAP Applications special resource agents for SAP HANA. With the pattern sap-hana the resource agent for SAP HANA ScaleUp is installed. For the ScaleOut scenario you need a special resource agent. Follow the instructions below on each node if you have installed the systems based on SAP note 2684254. The pattern High Availability summarizes all tools recommended to be installed on all nodes, including the majority maker.

• remove package: patterns-sap-hana, SAPHanaSR, yast2-sap-ha

• install package: SAPHanaSR-ScaleOut, SAPHanaSR-ScaleOut-doc, ClusterTools2, saptune

• install pattern: ha_sles

To do so, for example, use Zypper:

Example 1: Uninstall the SAPHanaSR agent for scale-up #

 

As user_root_ , type:

# zypper remove SAPHanaSR

If the package is installed, you will get an output like this:

Loading repository data...
Reading installed packages...
Resolving package dependencies...

The following 3 packages are going to be REMOVED:
  patterns-sap-hana SAPHanaSR yast2-sap-ha

The following pattern is going to be REMOVED:
  sap-hana

3 packages to remove.
After the operation, 494.2 KiB will be freed.
Continue? [y/n/...? shows all options] (y): y
(1/3) Removing patterns-sap-hana-15.3-6.8.2.x86_64 ..............................[done]
(2/3) Removing yast2-sap-ha-1.0.0-2.5.12.noarch .................................[done]
(3/3) Removing SAPHanaSR-0.161.21-1.1.noarch ....................................[done]

Example 2: Installation of the SAPHanaSR agent for scale-out #

 

As user root, type:

# zypper in SAPHanaSR-ScaleOut SAPHanaSR-ScaleOut-doc

If the package is not installed yet, you should get an output like the below:

Refreshing service 'Advanced_Systems_Management_Module_15_x86_64'.
Refreshing service 'SUSE_Linux_Enterprise_Server_for_SAP_Applications_15_SP3_x86_64'.
Loading repository data...
Reading installed packages...
Resolving package dependencies...

The following 2 NEW packages are going to be installed:
  SAPHanaSR-ScaleOut SAPHanaSR-ScaleOut-doc

2 new packages to install.
Overall download size: 539.1 KiB. Already cached: 0 B. After the operation, additional 763.1 KiB will be used.
Continue? [y/n/...? shows all options] (y): y
Retrieving package SAPHanaSR-ScaleOut-0.180.1-1.1.noarch                 (1/2),  48.7 KiB (211.8 KiB unpacked)
Retrieving: SAPHanaSR-ScaleOut-0.180.1-1.1.noarch.rpm ....................................[done]
Retrieving package SAPHanaSR-ScaleOut-doc-0.180.1-1.1.noarch             (2/2), 490.4 KiB (551.3 KiB unpacked)
Retrieving: SAPHanaSR-ScaleOut-doc-0.180.1-1.1.noarch.rpm ................................[done (48.0 KiB/s)]
Checking for file conflicts: .............................................................[done]
(1/2) Installing: SAPHanaSR-ScaleOut-0.180.1-1.1.noarch ..................................[done]
(2/2) Installing: SAPHanaSR-ScaleOut-doc-0.180.1-1.1.noarch ..............................[done]

Install the tools for High Availability on all nodes.

# zypper in --type pattern ha_sles

4.1.3 Getting the latest updates #

 

If you have installed the packages before, make sure to deploy the newest updates on all machines to have the latest versions of the resource agents and other packages. Also, make sure all systems have indentical package versions. A prerequisite is a valid subscription for SUSE Linux Enterprise Server for SAP Applications. There are multiple ways to get updates via SUSE Manager, the Repository Management Tool (RMT), or via a direct connection to the SUSE Customer Center (SCC).

Depending on your company or customer rules, use zypper update or zypper patch.

Example 3: Software update must be triggered from each node #

 

The command zypper patch will install all available needed patches. As user root, type:

# zypper patch

The command zypper update will update all or specified installed packages with newer versions, if possible. As user root, type:

# zypper update

Note

The new srHook script "SAPHanaSrMultiTarget.py" necessary for multi-target setup is not available in the installation ISO media and only available from update channels of SUSE Linux Enterprise Server for SAP Applications 15 SP3 or earlier. Thus, for a correctly working multi-target setup, a full system patching is mandatory. From SUSE Linux Enterprise Server for SAP Applications 15 SP4 onwards the "SAPHanaSrMultiTarget.py" will be included in the ISO.

4.2 Configuring SUSE Linux Enterprise Server for SAP Applications to run SAP HANA #

 

4.2.1 Tuning or modifying the operating system #

 

Operating system tuning are described in SAP note 1275776 and 2684254. The SAP note 1275776 explains three ways to implementing the settings.

Example 4: Using saptune (preferred) #

 

# saptune solution apply HANA

4.2.2 Enabling SSH access via public key (optional) #

 

Public key authentication provides SSH users access to their servers without entering their passwords. SSH keys are also more secure than passwords, because the private key used to secure the connection is never shared. Private keys can also be encrypted. Their encrypted contents cannot easily be read. For the document at hand, a very simple but useful setup is used. This setup is based on only one ssh-key pair which enables SSH access to all cluster nodes.

Note

Follow your company security policy to set up access to the systems.

Example 5: ssh key creation and exchange #

 

As user root create an SSH key on one node.

# ssh-keygen -t rsa

The ssh-key generation asks for missing parameters.

Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:ip/8kdTbYZNuuEUAdsaYOAErkwnkAPBR7d2SQIpIZCU root@<host1>
The key's randomart image is:
+---[RSA 2048]----+
|XEooo+ooo+o      |
|=+.= o=.o+.      |
|..B o. + o.      |
|   (°<           |
|  /  )           |
|   --            |
|   B. . o o =    |
|     o . . +     |
|      +.. .      |
+----[SHA256]-----+

After the ssh-keygen is set up, you will have two new files under /root/.ssh/ .

# ls /root/.ssh/
id_rsa  id_rsa.pub

Collect the public host keys from all other node. For the document at hand, the ssh-keyscan command is used.

# ssh-keyscan

The SSH host key is automatically collected and stored in the file /root/.ssh/known_host during the first SSH connection. To avoid to confirm the first login with "yes", which accepts the host key, collect and store them beforehand.

# ssh-keyscan -t ecdsa-sha2-nistp256 <host1>,<host1 ip> >>.ssh/known_hosts
# ssh-keyscan -t ecdsa-sha2-nistp256 <host2>,<host2 ip> >>.ssh/known_hosts
# ssh-keyscan -t ecdsa-sha2-nistp256 <host3>,<host3 ip> >>.ssh/known_hosts
...

After collecting all host keys store them in a file named authorized_keys. Push the entire directory /root/.ssh/ from the first node to all further cluster members.

# rsync -ay /root/.ssh/ <host2>:/root/.ssh/
# rsync -ay /root/.ssh/ <host3>:/root/.ssh/
# rsync -ay /root/.ssh/ <host4>:/root/.ssh/
...

4.2.3 Setting up disk layout for SAP HANA #

 

An SAP certified storage system with a validated storage API is generally recommended. This is a prerequisite of a stable and reliable scale-out installation.

• /hana/shared/<SID>

• /hana/data/<SID>

• /hana/log/<SID>

Create the mount directories on all SAP HANA nodes.

# mkdir -p /hana/shared/<SID>
# mkdir -p /hana/data/<SID>
# mkdir -p /hana/log/<SID>
# mkdir -p /usr/sap

The SAP HANA installation needs a special storage setup. The NFS setup used for this guide must be reboot-persistent. You can achieve this with entries in the /etc/fstab.

Note

NFS version 4 is required in the setup at hand.

Example 6: Create permanent mount entries for all NFS pools #

 

Create /etc/fstab entries for the three NFS pools.

<nfs>  /hana/shared/<SID>    nfs4  defaults  0 0

In the sample environment those lines are as follows:

/exports/TST_WDF1/shared  /hana/shared/TST      nfs4  defaults  0 0

Mount all NFS shares.

# mount -a

Create other directories (optional).

# mkdir -p /sapsoftware

File systems

/hana/shared/<SID>

The mount directory is used for shared files between all hosts in an SAP HANA system. Each HANA site has its own instance of this directory. It is accessible to the two nodes of that site. In our setup we use NFS.

/hana/log/<SID>

The default path to the log directory depends on the SAP System ID of the SAP HANA host. In our setup each HANA site has its own instance of this directory. It is accessible to the two nodes of that site. Each node has its own subdirectories. In our setup we use NFS. It would be possible be to use local disks instead.

/hana/data/<SID>

The default path to the data directory depends on the system ID of the SAP HANA host. In our setup each HANA site has its own instance of this directory. It is accessible to the two nodes of that site. Each node has its own subdirectories. In our setup we use NFS. It would be possible be to use local disks instead.

/usr/sap

This is the path to the local SAP system instance directories. It is possible to join this location with the Linux installation.

/sapsoftware

(optional) Space for copying the SAP install software media. This NFS pool is mounted on all HANA sites and contains the SAP HANA installation media and installation parameter files.

Set up host name resolution for all machines. You can either use a DNS server or modify the /etc/hosts on all nodes.

With maintaining the /etc/hosts file, you minimize the impact of a failing DNS service. Replace the IP address and the host name in the following commands.

# vi /etc/hosts

Insert the following lines to /etc/hosts. Change the IP address and host name to match your environment.

192.168.201.151 hanaso0
192.168.201.152 hanaso2
...

Enable NTP service on all nodes.

Simply enable an ntp service on all node in the cluster to have proper time synchronization.

# yast2 ntp-client

Figure 8: Section 3, “Planning the installation” [OsSetup] SAPHanaInst [SAPHanaHsr] Section 7, “Integrating SAP HANA with the Linux cluster” Section 8, “Configuring the cluster and SAP HANA resources” Section 9, “Setup of a scale-out multi-target architecture” [Testing] #

 

The infrastructure is set up. Now install the SAP HANA database at both sites. This chapter summarizes the test environment. In a cluster a machine is also called a node. Always use the official documentation from SAP to install SAP HANA and to set up the system replication.

This guide shows SAP HANA and saphostagent with native systemd integration. An example for legacy SystemV is outlined in the appendix Section 11.3, “Example for checking legacy SystemV integration”.

In the example at hand, to make it easier to follow the documentation, the machines (or nodes) are named hanaso0, …​ hanasoX. The nodes (hanaso0, hanaso1) will be part of site "A" (WDF1), the nodes (hanaso2, hanaso3) will be part of site "B" (ROT1), and the nodes (hanaso4, hanaso5) will be part of site "C" (FRA1).

The following users are automatically created during the SAP HANA installation:

# systemctl list-unit-files | grep sap
saphostagent.service enabled
sapinit.service generated
saprouter.service disabled
saptune.service enabled

# systemctl list-unit-files | grep SAP
SAPTST_00.service enabled

# systemd-cgls -u SAP.slice
Unit SAP.slice (/SAP.slice):
├─saphostagent.service
│ ├─2630 /usr/sap/hostctrl/exe/saphostexec pf=/usr/sap/hostctrl/exe/host_profile -systemd
│ ├─2671 /usr/sap/hostctrl/exe/sapstartsrv pf=/usr/sap/hostctrl/exe/host_profile -D
│ └─3591 /usr/sap/hostctrl/exe/saposcol -l -w60 pf=/usr/sap/hostctrl/exe/host_profile
└─SAPTST_00.service
  ├─ 1257 hdbcompileserver
  ├─ 1274 hdbpreprocessor
  ├─ 1353 hdbindexserver -port 31003
  ├─ 1356 hdbxsengine -port 31007
  ├─ 2077 hdbwebdispatcher
  ├─ 2300 hdbrsutil --start --port 31003 --volume 3 --volumesuffix mnt00001/hdb00003.00003 --identifier 1644426276
  ├─28462 /usr/sap/TST/HDB00/exe/sapstartsrv pf=/usr/sap/TST/SYS/profile/TST_HDB00_hanaso0
  ├─31314 sapstart pf=/usr/sap/TST/SYS/profile/TST_HDB00_hanaso0
  ├─31372 /usr/sap/TST/HDB00/hanaso0/trace/hdb.sapTST_HDB00 -d -nw -f /usr/sap/TST/HDB00/suse21/daemon.ini pf=/usr/sap/TST/SYS/profile/TST_HDB00_hanaso1
  ├─31479 hdbnameserver
  └─32201 hdbrsutil --start --port 31001 --volume 1 --volumesuffix mnt00001/hdb00001 --identifier 1644426203

~> HDBSettings.sh landscapeHostConfiguration.py

| Host   | Host   |... NameServer  | NameServer  | IndexServer | IndexServer
|        | Active |... Config Role | Actual Role | Config Role | Actual Role
| ------ | ------ |... ----------- | ----------- | ----------- | -----------
| hanaso0 | yes    |... master 1    | master      | worker      | master
| hanaso1 | yes    |... master 2    | slave       | worker      | slave

overall host status: ok

~> sapcontrol -nr <instanceNumber> -function GetSystemInstanceList
25.07.2022 17:25:16
GetSystemInstanceList
OK
hostname, instanceNr, httpPort, httpsPort, startPriority, features, dispstatus
hanaso0, 00, 50013, 50014, 0.3, HDB|HDB_WORKER, GREEN
hanaso1, 00, 50013, 50014, 0.3, HDB|HDB_WORKER, GREEN

Figure 9: Section 3, “Planning the installation” [OsSetup] [SAPHanaInst] SAPHanaHsr Section 7, “Integrating SAP HANA with the Linux cluster” Section 8, “Configuring the cluster and SAP HANA resources” Section 9, “Setup of a scale-out multi-target architecture” [Testing] #

 

This section describes the setup of the system replication (HSR) after SAP HANA has been installed properly.

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

6.1 Backing up the primary database #

 

First back up the primary database as described in the SAP HANA Administration Guide, Section SAP HANA Database Backup and Recovery.

Below find examples to back up SAP HANA with SQL Commands:

Example 11: Simple backup for the system database and all tenants with one singe backup call #

 

As user <sid>adm enter the following command:

~> hdbsql -i {refInst} -u SYSTEM -d SYSTEMDB \
   "BACKUP DATA FOR FULL SYSTEM USING FILE ('backup')"

You get the following command output (or similar):

0 rows affected (overall time 15.352069 sec; server time 15.347745 sec)

Example 12: 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

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

~> hdbnsutil -sr_enable --name=WDF1

nameserver is active, proceeding ...
successfully enabled system as system replication source site
done.

~> hdbnsutil -sr_stateConfiguration

checking for active or inactive nameserver ...
System Replication State
~~~~~~~~~~~~~~~~~~~~~~~~

mode: primary
site id: 1
site name: WDF1
done.

~> sapcontrol -nr <instanceNumber> -function StopSystem

cd /usr/sap/<SID>/SYS/global/security/rsecssfs
rsync -va {,<node1-siteB>:}$PWD/data/SSFS_<SID>.DAT
rsync -va {,<node1-siteB>:}$PWD/key/SSFS_<SID>.KEY

~> hdbnsutil -sr_register --name=<site2> \
     --remoteHost=<node1-siteA> --remoteInstance=<instanceNumber> \
     --replicationMode=sync --operationMode=logreplay

adding site ...
checking for inactive nameserver ...
nameserver hanaso2:30001 not responding.
collecting information ...
updating local ini files ...
done.

~> sapcontrol -nr <instanceNumber> -function StartSystem

~> hdbnsutil -sr_stateConfiguration

System Replication State
~~~~~~~~~~~~~~~~~~~~~~~~
mode: sync
site id: 2
site name: ROT1
active primary site: 1

primary masters: hanaso0 hanaso1
done.

~> HDBSettings.sh systemReplicationStatus.py

| Database | Host   | .. Site Name | Secondary | .. Secondary | .. Replication
|          |        | ..           | Host      | .. Site Name | .. Status
| -------- | ------ | .. --------- | --------- | .. --------- | .. ------
| SYSTEMDB | hanaso0 | .. WDF1      | hanaso2  | .. ROT1      | .. ACTIVE
| TST      | hanaso0 | .. WDF1      | hanaso2  | .. ROT1      | .. ACTIVE
| TST      | hanaso0 | .. WDF1      | hanaso2  | .. ROT1      | .. ACTIVE
| TST      | hanaso1 | .. WDF1      | hanaso3  | .. ROT1      | .. ACTIVE

status system replication site "2": ACTIVE
overall system replication status: ACTIVE

Local System Replication State
~~~~~~~~~~

mode: PRIMARY
site id: 1
site name: WDF1

Figure 10: Section 3, “Planning the installation” [OsSetup] [SAPHanaInst] [SAPHanaHsr] Integration Section 8, “Configuring the cluster and SAP HANA resources” Section 9, “Setup of a scale-out multi-target architecture” [Testing] #

 

This chapter describes what to change on the SAP HANA configuration for the ERP style scale-out multi-target scenario.

Note

All hook scripts should be used directly from the SAPHanaSR-ScaleOut package. If the scripts are moved or copied, regular SUSE package updates will not work.

# su - <sid>adm
~> sapcontrol -nr <instanceNumber> -function StopSystem
~> sapcontrol -nr <instanceNumber> -function WaitforStopped 300 20
~> sapcontrol -nr <instanceNumber> -function GetSystemInstanceList

[system_replication]
operation_mode = logreplay
register_secondaries_on_takeover = true

[landscape]
...
master = hanaso0:30001 hanaso1:30001
worker = hanaso0 hanaso1
active_master = hanaso0:30001

[landscape]
...
master = hanaso0:30001
worker = hanaso0 hanaso1
active_master = hanaso0:30001

[ha_dr_provider_saphanasrmultitarget]
provider = SAPHanaSrMultiTarget
path = /usr/share/SAPHanaSR-ScaleOut/
execution_order = 1

[trace]
ha_dr_saphanasrmultitarget = info

[ha_dr_provider_suschksrv]
provider = susChkSrv
path = /usr/share/SAPHanaSR-ScaleOut/
execution_order = 3
action_on_lost = stop

[trace]
ha_dr_suschksrv = info

[ha_dr_provider_sustkover]
provider = susTkOver
path = /usr/share/SAPHanaSR-ScaleOut/
execution_order = 2
sustkover_timeout = 30

[trace]
ha_dr_sustkover = info

# SAPHanaSR-ScaleOut needs for HA/DR hook scripts
<sid>adm ALL=(ALL) NOPASSWD: /usr/sbin/crm_attribute -n hana_<sid>_site_srHook_*
<sid>adm ALL=(ALL) NOPASSWD: /usr/sbin/crm_attribute -n hana_<sid>_gsh *
<sid>adm ALL=(ALL) NOPASSWD: /usr/sbin/crm_attribute -n hana_<sid>_glob_mts *
<sid>adm ALL=(ALL) NOPASSWD: /usr/sbin/SAPHanaSR-hookHelper --sid=<SID> *

# sudo -U <sid>adm -l | grep "NOPASSWD"

~> sapcontrol -nr <instanceNumber> -function StartSystem

11.11.2022 11:11:01
StartSystem
OK

~> sapcontrol -nr <instanceNumber> -function WaitforStarted 300 20
~> sapcontrol -nr <instanceNumber> -function GetSystemInstanceList

~> cdtrace
~> grep HADR.*load.*SAPHanaSrMultiTarget nameserver_*.trc | tail -3
~> grep SAPHanaSr.*init nameserver_*.trc | tail -3
~> grep -A5 "init.called" nameserver_saphanasr_multitarget_hook.trc

~> cdtrace
~> grep HADR.*load.*susChkSrv nameserver_*.trc | tail -3
~> grep susChkSrv.init nameserver_*.trc | tail -3

~> cdtrace
~> grep HADR.*load.*susTkOver nameserver_*.trc | tail -3
~> grep susTkOver.init nameserver_*.trc | tail -3

Figure 11: Section 3, “Planning the installation” [OsSetup] [SAPHanaInst] [SAPHanaHsr] Section 7, “Integrating SAP HANA with the Linux cluster” Cluster Section 9, “Setup of a scale-out multi-target architecture” [Testing] #

 

This chapter describes the configuration of the SUSE Linux Enterprise High Availability Extension cluster. The SUSE Linux Enterprise High Availability Extension is part of SUSE Linux Enterprise Server for SAP Applications. Further, the integration of SAP HANA System Replication with the SUSE Linux Enterprise High Availability Extension cluster is explained. The integration is done by using the SAPHanaSR-ScaleOut package which is also part of SUSE Linux Enterprise Server for SAP Applications.

# zypper in -t pattern ha_sles

# zypper in SAPHanaSR-ScaleOut

# zypper patch

8.2 Configuring the basic cluster #

 

After having installed the cluster packages, the next step is to set up the basic cluster framework. For convenience, use YaST or the ha-cluster-init script.

Important

It is strongly recommended to add a second corosync ring, implement unicast (UCAST) communication and adjust the timeout values to your environment.

Prerequisites

• Name resolution

• Time synchronization

• Redundant network for cluster intercommunication

• STONITH method

8.2.1 Seting up watchdog for "Storage-based Fencing" #

 

It is recommended to use SBD as central STONITH device, as done in the example at hand. Each node constantly monitors connectivity to the storage device, and terminates itself in case the partition becomes unreachable. Whenever SBD is used, a correctly working watchdog is crucial. Modern systems support a hardware watchdog that needs to be "tickled" or "fed" by a software component. The software component (usually a daemon) regularly writes a service pulse to the watchdog. If the daemon stops feeding the watchdog, the hardware will enforce a system restart. This protects against failures of the SBD process itself, such as dying, or getting stuck on an I/O error.

Example 26: Set up for Watchdog #

 

Important

Access to the Watchdog Timer: No other software must access the watchdog timer. Some hardware vendors ship systems management software that uses the watchdog for system resets (for example, HP ASR daemon). Disable such software, if watchdog is 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 which 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

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

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

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.

# touch /dev/watchdog

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

# echo 1 > /dev/watchdog

After your test was successful you can implement the watchdog on all cluster members. The example below applies to the softdog module. Replace <wrong_module> by the module name queried before.

# for i in hana{so0,so1,so2,so3,mm}; do
    ssh -T $i <<EOSSH
        hostname
        rmmod <wrong_module>
        echo softdog > /etc/modules-load.d/watchdog.conf
        systemctl restart systemd-modules-load
        lsmod |grep -e dog
EOSSH
done

8.2.2 Basic cluster configuration using ha-cluster-init #

 

For more detailed information about ha-cluster-* tools, see section Overview of the Bootstrap Scripts of the Installation and Setup Quick Start Guide for SUSE Linux Enterprise High Availability Extension at https://documentation.suse.com/sle-ha/15-SP1/single-html/SLE-HA-install-quick/#sec-ha-inst-quick-bootstrap.

Create an initial setup by using the ha-cluster-init command. Follow the dialog steps.

Note

This is only to be done on the first cluster node. If you are using SBD as STONITH mechanism, you need to first load the watchdog kernel module matching your setup. In the example at hand the softdog kernel module is used.

The command ha_cluster-init 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

# ha-cluster-init -u -s <sbd-device>

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

Note

Do not forget to change the password of the user hacluster.

8.2.3 Cluster configuration for all other cluster nodes #

 

The other nodes of the cluster could be integrated by starting the command ha-cluster-join. This command asks for the IP address or name of the first cluster node. Than all needed configuration files are copied over. As a result the cluster is started on all nodes. Do not forget the majority maker.

If you are using SBD as STONITH method, you need to activate the softdog kernel module matching your systems. In the example at hand the softdog kernel module is used.

# ha-cluster-join -c <host1>

8.2.4 Checking the cluster for the first time #

 

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

# crm cluster run "crm cluster start"

Note

All nodes should be started in parallel. Otherwise unseen nodes might get fenced.

Check whether all cluster nodes have registered at the SBD device(s). See manual page cs_show_sbd_devices(8) for details.

# cs_show_sbd_devices

Check the cluster status with crm_mon. Use the option -r to also see resources which are configured but stopped.

# crm_mon -r

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

Stack: corosync
Current DC: hanamm (version 1.1.16-4.8-77ea74d) - partition with quorum
Last updated: Mon July 25 16:55:04 2022
Last change: Mon July 25 16:53:58 2022 by root via crm_attribute on hanaso2

7 nodes configured
1 resource configured

Online: [ hanamm hanaso0 hanaso1 hanaso2 hanaso3 ]

Full list of resources:

stonith-sbd     (stonith:external/sbd): Started hanamm

8.3 Configuring cluster properties and resources #

 

This section describes how to configure bootstrap, STONITH, resources, and constraints using the crm configure shell command as described in section Configuring and Managing Cluster Resources (Command Line) of the SUSE Linux Enterprise High Availability Extension Administration Guide (see https://documentation.suse.com/sle-ha/15-SP1/html/SLE-HA-all/cha-ha-manual-config.html).

Use the command crm to add the objects to the Cluster Resource Management (CRM). Copy the following examples to a local file and then load the configuration to the Cluster Information Base (CIB). The benefit is that you have a scripted setup and a backup of your configuration.

Perform all crm commands only on one node, for example on machine hanaso0.

First write a text file with the configuration, which you load into your cluster in a second step. This step is as follows:

# vi crm-file<XX>
# crm configure load update crm-file<XX>

8.3.1 Cluster bootstrap and more #

 

The first example defines the cluster bootstrap options including the resource and operation defaults.

The stonith-timeout should be greater than 1.2 times the SBD msgwait timeout. Find more details and examples in manual page SAPHanaSR-ScaleOut_basic_cluster(7).

# vi crm-bs.txt

Enter the following to crm-bs.txt:

property cib-bootstrap-options: \
    have-watchdog=true \
    cluster-infrastructure=corosync \
    cluster-name=hacluster \
    placement-strategy=balanced \
    no-quorum-policy=freeze \
    stonith-enabled=true \
    concurrent-fencing=true \
    stonith-action=reboot \
    stonith-timeout=150
rsc_defaults rsc-options: \
    resource-stickiness=1000 \
    migration-threshold=50
op_defaults op-options: \
    timeout=600 \
    record-pending=true

Now add the configuration to the cluster.

# crm configure load update crm-bs.txt

8.3.2 STONITH #

 

As already explained in the requirements, STONITH is crucial for a supported cluster setup. Without a valid fencing mechanism your cluster is unsupported.

A standard STONITH mechanism implements SBD based fencing. The SBD STONITH method is very stable and reliable and has proved very good road capability.

You can use other fencing methods available for example from your public cloud provider. However, it is crucial to intensively test the server fencing.

For SBD based fencing you can use one up to three SBD devices. The cluster will react differently when an SBD device is lost. The differences and SBD fencing are explained very well in the SUSE product documentation of the SUSE Linux Enterprise High Availability Extension available at https://documentation.suse.com/.

You need to adapt the SBD resource for the SAP HANA scale-out cluster.

As user <sid>adm create a file named for crm-fencing.txt.

Example 27: Configure fencing #

 

# vi crm-fencing.txt

Enter the following to crm-fencing.txt:

primitive stonith-sbd stonith:external/sbd \
	params pcmk_action_limit=-1 pcmk_delay_max=1

Now load the configuration from the file to the cluster.

# crm configure load update crm-fencing.txt

8.3.3 Cluster in maintenance mode #

 

Load the configuration for the resources and the constraints step-by-step to the cluster to explain the different parts. The best way to avoid unexpected cluster reactions is to

• first set the complete cluster to maintenance mode,

• then do all needed changes and,

• as last step, end the cluster maintenance mode.

# crm maintenance on

8.3.4 SAPHanaTopology #

 

Next, define the group of resources needed, before the SAP HANA instances can be started. Prepare the changes in a text file, for example crm-saphanatop.txt, and load these with the crm command.

If necessary, change the SID and instance number (bold) to appropriate values for your setup.

Example 28: Configure SAPHanaTopology #

 

hanaso0:~ # vi crm-saphanatop.txt

Enter the following to crm-saphanatop.txt:

primitive rsc_SAPHanaTop_<SID>_HDB<instanceNumber> ocf:suse:SAPHanaTopology \
    op monitor interval="10" timeout="600" \
    op start interval="0" timeout="600" \
    op stop interval="0" timeout="300" \
    params SID="<SID>" InstanceNumber="<instanceNumber>"

clone cln_SAPHanaTop_<SID>_HDB<instanceNumber> rsc_SAPHanaTop_<SID>_HDB<instanceNumber> \
    meta clone-node-max="1" interleave="true"

primitive rsc_SAPHanaTop_TST_HDB00 ocf:suse:SAPHanaTopology \
    op monitor interval="10" timeout="600" \
    op start interval="0" timeout="600" \
    op stop interval="0" timeout="300" \
    params SID="TST" InstanceNumber="00"

clone cln_SAPHanaTop_TST_HDB00 rsc_SAPHanaTop_TST_HDB00 \
    meta clone-node-max="1" interleave="true"

For additional information about all parameters, use the command man ocf_suse_SAPHanaTopology.

Again, add the configuration to the cluster.

# crm configure load update crm-saphanatop.txt

The most important parameters here are SID (TST) and InstanceNumber (00), which are self explaining in an SAP context. Beside these parameters, the timeout values or the operations (start, monitor, stop) are typical values to be adjusted for your environment.

8.3.5 SAPHanaController #

 

Next, define the group of resources needed, before the SAP HANA instances can be started. Edit the changes in a text file, for example crm-saphanacon.txt and load these with the command crm.

# vi crm-saphanacon.txt

Example 29: Configure SAPHanaController #

 

Enter the following to crm-saphanacon.txt

primitive rsc_SAPHanaCon_<SID>_HDB<instanceNumber> ocf:suse:SAPHanaController \
    op start interval="0" timeout="3600" \
    op stop interval="0" timeout="3600" \
    op promote interval="0" timeout="3600" \
    op demote interval="0" timeout="320" \
    op monitor interval="60" role="Master" timeout="700" \
    op monitor interval="61" role="Slave" timeout="700" \
    params SID="<SID>" InstanceNumber="<instanceNumber>" \
        PREFER_SITE_TAKEOVER="true" \
        DUPLICATE_PRIMARY_TIMEOUT="7200" AUTOMATED_REGISTER="false" \
        HANA_CALL_TIMEOUT="120"

ms msl_SAPHanaCon_<SID>_HDB<instanceNumber> \
    rsc_SAPHanaCon_<SID>_HDB<instanceNumber> \
    meta master-node-max="1" master-max="1" clone-node-max="1" interleave="true" \
    maintenance="true"

The most important parameters here are <SID> (TST) and <instanceNumber> (00), which are in the SAP context quite self explaining. Beside these parameters, the timeout values or the operations (start, monitor, stop) are typical tuneables. Find more details in manual page ocf_suse_SAPHanaTopology(7).

primitive rsc_SAPHanaCon_TST_HDB00 ocf:suse:SAPHanaController \
    op start interval="0" timeout="3600" \
    op stop interval="0" timeout="3600" \
    op promote interval="0" timeout="900" \
    op demote interval="0" timeout="320" \
    op monitor interval="60" role="Master" timeout="700" \
    op monitor interval="61" role="Slave" timeout="700" \
    params SID="TST" InstanceNumber="00" PREFER_SITE_TAKEOVER="true" \
        DUPLICATE_PRIMARY_TIMEOUT="7200" AUTOMATED_REGISTER="false" \
        HANA_CALL_TIMEOUT="120"

ms msl_SAPHanaCon_TST_HDB00 rsc_SAPHanaCon_TST_HDB00 \
    meta master-node-max="1" master-max="1" clone-node-max="1" interleave="true" \
    maintenance="true"

Add the configuration to the cluster.

# crm configure load update crm-saphanacon.txt

Table 2: Table Description of important Resource Agent parameter #

 

Name	Description
PREFER_SITE_TAKEOVER	Defines whether RA should prefer to takeover to the secondary instance instead of restarting the failed primary locally. Set to true for SAPHanaSR-ScaleOut.
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 sites in a "WAITING" status. This is to give an administrator the chance to react on a failover. 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, then 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 command man ocf_suse_SAPHana_Controller.

8.3.6 The virtual IP address of the HANA primary #

 

The last mandatory resource to be added to the cluster is covering the virtual IP address for the HANA primary master name server. Replace the bold string with your instance number, SAP HANA system ID and the virtual IP address.

Example 30: Configure the virtual IP address of the primary #

 

# vi crm-vip.txt

Enter the following to crm-vip.txt:

primitive rsc_ip_<SID>_HDB<instanceNumber> ocf:heartbeat:IPaddr2 \
    op monitor interval="10s" timeout="20s" \
    params ip="<IP>"

Example 31: Replace <SID> by TST, <instanceNumber> by 00, <IP> by 192.7.7.20 #

 

primitive rsc_ip_TST_HDB00 ocf:heartbeat:IPaddr2 \
    op monitor interval="10s" timeout="20s" \
    params ip="192.7.7.20"

Load the file to the cluster.

# crm configure load update crm-vip.txt

In most installations, only the parameter ip needs to be set to the virtual IP address to be presented to the client systems. Use the command man ocf_heartbeat_IPaddr2 for details on additional parameters.

8.3.7 Constraints #

 

The 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 SAPHanaController and SAPHanaTopology.

Example 32: Configure needed constraints #

 

# vi crm-cs.txt

Enter the following to crm-cs.txt:

colocation col_saphana_ip_<SID>_HDB<instanceNumber> 2000: rsc_ip_<SID>_HDB<instanceNumber>:Started \
    msl_SAPHanaCon_<SID>_HDB<instanceNumber>:Master

order ord_SAPHana_<SID>_HDB<instanceNumber> Optional: cln_SAPHanaTop_<SID>_HDB<instanceNumber> \
    msl_SAPHanaCon_<SID>_HDB<instanceNumber>

location SAPHanaCon_not_on_majority_maker msl_SAPHanaCon_<SID>_HDB<instanceNumber> \
    -inf: <majority maker>
location SAPHanaTop_not_on_majority_maker cln_SAPHanaTop_<SID>_HDB<instanceNumber> \
    -inf: <majority maker>

Example 33: Replace <SID> by TST, <instanceNumber> by 00 #

 

colocation col_saphana_ip_TST_HDB00 2000: rsc_ip_TST_HDB00:Started \
    msl_SAPHanaCon_TST_HDB00:Master

order ord_SAPHana_TST_HDB00 Optional: cln_SAPHanaTop_TST_HDB00 \
    msl_SAPHanaCon_TST_HDB00

location SAPHanaCon_not_on_majority_maker msl_SAPHanaCon_TST_HDB00 -inf: hanamm
location SAPHanaTop_not_on_majority_maker cln_SAPHanaTop_TST_HDB00 -inf: hanamm

Load the file to the cluster.

# crm configure load update crm-cs.txt

8.3.8 The virtual IP address of the HANA read-enabled secondary #

 

This optional resource is covering the virtual IP address for the read-enabled HANA secondary master name server. It is useful if SAP HANA is configured with the active/read-enabled feature. Replace the bold string with your instance number, SAP HANA system ID and the virtual IP address.

Note

In scale-out this works only for an SAP HANA topology with exactly one master name server and exactly one slave node.

Example 34: Configure the virtual IP address of the read-enabled secondary #

 

# vi crm-vip-ro.txt

Enter the following to crm-vip-ro.txt:

primitive rsc_ip_ro_<SID>_HDB<instanceNumber> ocf:heartbeat:IPaddr2 \
    op monitor interval="10s" timeout="20s" \
    params ip="<IP-ro>"
colocation col_ip_ro_with_secondary_<SID>_HDB<instanceNumber> \
    2000: rsc_ip_ro_<SID>_HDB<instanceNumber>:Started \
    msl_SAPHanaCon_<SID>_HDB<instanceNumber>:Slave
location loc_ip_ro_not_master_<SID>_HDB<instanceNumber> \
    rsc_ip_ro_<SID>_HDB<instanceNumber> \
    rule -inf: hana_<sid>_roles ne master1:master:worker:master

Example 35: Replace <SID> by TST, <instanceNumber> by 00, <IP-ro> by 192.168.201.161 #

 

primitive rsc_ip_ro_TST_HDB00 ocf:heartbeat:IPaddr2 \
    op monitor interval="10s" timeout="20s" \
    params ip="192.168.201.161"
colocation col_ip_ro_with_secondary_TST_HDB00 \
    2000: rsc_ip_ro_TST_HDB00:Started \
    msl_SAPHanaCon_TST_HDB00:Slave
location loc_ip_ro_not_master_TST_HDB00 \
    rsc_ip_ro_TST_HDB00 \
    rule -inf: hana_tst_roles ne master1:master:worker:master

Load the file to the cluster.

# crm configure load update crm-vip-ro.txt

In most installations, only the parameter ip needs to be set to the virtual IP address to be presented to the client systems. Use the command man ocf_heartbeat_IPaddr2 for details on additional parameters. See also manual page SAPHanaSR-ScaleOut_basic_cluster(7).

# crm_attribute -G -n hana_<sid>_glob_srHook

scope=crm_config name=hana_<sid>_glob_srHook value=SFAIL

hanaso0:tstadm> /usr/sap/hostctrl/exe/saphostctrl -function ListInstances
 Inst Info : HA1 - 00 - hanaso0 - 749, patch 418, changelist 1816226

# crm maintenance off
# cs_wait_for_idle -s 5
# crm resource refresh msl_SAPHanaCon_TST_HDB00
# cs_wait_for_idle -s 5
# crm resource maintenance msl_SAPHanaCon_TST_HDB00 off

Figure 12: Section 3, “Planning the installation” [OsSetup] [SAPHanaInst] [SAPHanaHsr] Section 7, “Integrating SAP HANA with the Linux cluster” Section 8, “Configuring the cluster and SAP HANA resources” MultiTarget [Testing] #

 

This chapter is divided into two sections. Both are optional, depending oon your needs.

~> hdbnsutil -sr_register --name=FRA1 --remoteHost=hanaso0 --remoteInstance=00 --replicationMode=async --operationMode=logreplay

hanaso0:~ # SAPHanaSR-showAttr
Global cib-time                 maintenance prim sec  sync_state upd
---------------------------------------------------------------------
TST    Fri Jul 15 00:44:25 2022 false       WDF1 ROT1 SOK        ok

Sites lpt        lss mns     srHook srr
----------------------------------------
FRA1                         SOK
ROT1  30         4   hanaso2 SOK    S
WDF1  1657838665 4   hanaso0 PRIM   P

Hosts   clone_state gra gsh node_state roles                        score  site
--------------------------------------------------------------------------------
hanamm                      online
hanaso0 PROMOTED    2.0 2.2 online     master1:master:worker:master 150    WDF1
hanaso1 DEMOTED     2.0 2.2 online     slave:slave:worker:slave     -10000 WDF1
hanaso2 DEMOTED     2.0 2.2 online     master1:master:worker:master 100    ROT1
hanaso3 DEMOTED     2.0 2.2 online     slave:slave:worker:slave     -12200 ROT1

hanaso0:~ #

Figure 13: Section 3, “Planning the installation” [OsSetup] [SAPHanaInst] [SAPHanaHsr] Section 7, “Integrating SAP HANA with the Linux cluster” Section 8, “Configuring the cluster and SAP HANA resources” Section 9, “Setup of a scale-out multi-target architecture” Testing #

 

Testing is one of the most important project tasks for implementing clusters. Proper testing is crucial. Make sure that all test cases derived from project or customer expectations are defined and passed completely. Without testing the project is likely to fail in production use.

The test prerequisite, if not described differently, is always that all cluster nodes are booted, are already normal members of the cluster and the SAP HANA RDBMS is running. The system replication is in state SYNC represented by 'srHook SOK' for the secondary site. The cluster is idle, no actions are pending, no migration constraints left over, no failcounts left over.

The expected results are given for SAPHanaController parameter AUTOMATED_REGISTER="false" and SBD parameter SBD_START_MODE="always". These are installation defaults. Further susChkSrv.py parameter action_on_lost="stop" is used.

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