SAP HANA System Replication Scale-Up - Performance Optimized Scenario #

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:

You need at least SAPHanaSR version 0.152 and in best SUSE Linux Enterprise Server for SAP Applications 12 SP4 or newer. SAP HANA 1.0 is supported since SPS09 (095) for all mentioned setups. SAP HANA 2.0 is supported with all known SPS versions.

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 PoC with SUSE. This PoC will focus on testing the existing solution in your scenario. Most of the above mentioned limitations are because careful testing is needed.

Besides SAP HANA, you need SAP Host Agent to be installed on your system.

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.

Figure 7: Cluster with SAP HANA SR - performance optimized #

 

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

If you like 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 available at: https://documentation.suse.com/sles-sap/12-SP4/single-html/SLES4SAP-guide/#cha-s4s-cluster

Figure 8: 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:

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

What you need before you start:

4.1 Minimum Lab Requirements and Prerequisites #

 

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.

Note

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

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

• 2 VMs with each 32GB RAM, 50GB 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 96GB for SAP HANA

• 1 additional IP address for takeover

• 1 optional IP address for the read-enabled setup

• 1 optional IP address for HAWK Administration GUI

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

• 2 VMs with each 32GB RAM, 50GB disk space for the system

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

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

• 1 additional IP address for takeover

• 1 optional IP address for the read-enabled setup

• 1 optional IP address for HAWK Administration GUI

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.

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.

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

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

Procedure

7.1 Back 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 2: Simple backup for the system database and all tenants with one single backup call #

 

As user <sidadm> enter the following command:

hdbsql -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 3: Simple backup for a single container (non MDC) database #

 

Enter the following command as user <sidadm>:

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.

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

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

Example 4: 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 5: 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” and the site now has a site name and a site ID.

suse02:~> HDB stop

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

...
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.

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.

suse01:~> HDBSettings.sh systemReplicationStatus.py --sapcontrol=1
...
site/2/SITE_NAME=ROT1
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=WDF1
local_site_id=1
...

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

8.1 Implementing the Python Hook SAPHanaSR #

 

This step must be done 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. Use the hook script SAPHanaSR.py from the SAPHanaSR package (available since version 0.153). See manual pages SAPHanaSR.py(7) and SAPHanaSR-manageProvider(8) for details.

• Integrate the hook into global.ini (SAP HANA needs to be stopped for doing that offline)

• Check integration of the hook during start-up

Note

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

Example 11: Stop SAP HANA #

 

Stop SAP HANA either with HDB or using sapcontrol.

~> sapcontrol -nr <instanceNumber> -function StopSystem

Example 12: Adding SAPHanaSR via global.ini #

 

[ha_dr_provider_SAPHanaSR]
provider = SAPHanaSR
path = /usr/share/SAPHanaSR
execution_order = 1

[trace]
ha_dr_saphanasr = info

[system_replication]
operation_mode = logreplay

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

# 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
<sidadm> ALL=(ALL) NOPASSWD: SOK_SITEA, SFAIL_SITEA, SOK_SITEB, SFAIL_SITEB

This chapter describes the configuration of the cluster software SUSE Linux Enterprise High Availability Extension, which is part of the SUSE Linux Enterprise Server for SAP Applications, and SAP HANA Database 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 to UCAST communication and adjust the timeout values to your environment.

9.1.1 Set up Watchdog for "Storage-based Fencing" #

 

If you use the SBD fencing mechanism (disk-less or disk-based), you must also configure a watchdog. The watchdog is needed to reset a node if the system could not longer access the SBD (disk-less or disk-based). It is mandatory that to configure the Linux system to load 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 a fall-back, you can use the softdog module.

Example 15: Set up for Watchdog #

 

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 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
# ls -l /dev/watchdog

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 controlled by 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 must implement the watchdog on all cluster members.

9.1.2 Initial Cluster Setup Using ha-cluster-init #

 

For more information, see Automatic Cluster Setup, SUSE Linux Enterprise High Availability Extension.

Create an initial setup, using ha-cluster-init command and follow the dialogs. This has only to be done 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

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 SBD Config #

 

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

See man pages sbd.8 and stonith_sbd.7 for details.

Table 3: SBD Options #

 

Parameter	Description
-W	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. This is equivalent to SBD_WATCHDOG="yes"
-S 1	Start mode. If set to one, sbd will only start if the node was previously shut down cleanly or if the slot is empty. This is equivalent to SBD_STARTMODE="clean"
-P	Check Pacemaker quorum and node health. This is equivalent to SBD_PACEMAKER="yes"

In the following, 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=""

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.

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 sample are only start values, which 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 Storage-based Fencing, SUSE Linux Enterprise High Availability Extension and 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 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 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
suse01:~ # systemctl start pacemaker
suse02:~ # systemctl status sbd
suse02:~ # systemctl start pacemaker

Check the cluster status with crm_mon. We 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 following screen output. 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

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

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="5000"
op_defaults $id="op-options" \
                 timeout="600"

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

# vi crm-sbd.txt
# enter the following to crm-sbd.txt
primitive stonith-sbd stonith:external/sbd \
    params pcmk_delay_max="15"

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

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

# 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="true" \
        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"

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

# 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"

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

# 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

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

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

primitive rsc_ip_HA1_HDB10_readenabled ocf:heartbeat:IPaddr2 \
        op monitor interval="10s" timeout="20s" \
        params ip="192.168.1.21"
colocation col_saphana_ip_HA1_HDB10_readenabled 2000: \
    rsc_ip_HA1_HDB10_readenabled:Started msl_SAPHana_HA1_HDB10:Slave

The lists of tests will be improved in the next update of this document.

As with any cluster testing is crucial. Make sure that all test cases derived from customer expectations are implemented and passed fully. Otherwise the project is likely to fail in production.

The test prerequisite, if not described differently, is always that both nodes are booted, normal members of the cluster and the HANA RDBMS is running. The system replication is in sync (SOK).

10.1 Test Cases for Semi Automation #

 

In the following test descriptions we assume PREFER_SITE_TAKEOVER="true" and AUTOMATED_REGISTER="false".

Note

The following tests are designed to be run in sequence and depend on the exit state of the proceeding tests.

10.1.1 Test: Stop Primary Database on Site A (Node 1) #

 

Example 16: Test STOP_PRIMARY_SITE_A #

 

Component: #

 

• Primary Database

Description: #

 

• The primary HANA database is stopped during normal cluster operation.

Test Procedure: #

 

1. Stop the primary HANA database gracefully as <sid>adm.

   suse01# HDB stop

Recovery Procedure: #

 

1. Manually register the old primary (on node 1) with the new primary after takeover (on node 2) as <sid>adm.

   suse01# hdbnsutil -sr_register --remoteHost=suse02 --remoteInstance=10 \
             --replicationMode=sync --operationMode=logreplay \
             --name=WDF

2. Restart the HANA database (now secondary) on node 1 as root.

   suse01# crm resource refresh rsc_SAPHana_HA1_HDB10 suse01

Expected: #

 

1. The cluster detects the stopped primary HANA database (on node 1) and marks the resource failed.

2. The cluster promotes the secondary HANA database (on node 2) to take over as primary.

3. The cluster migrates the IP address to the new primary (on node 2).

4. After some time the cluster shows the sync_state of the stopped primary (on node 1) as SFAIL.

5. Because AUTOMATED_REGISTER="false" the cluster does not restart the failed HANA database or register it against the new primary.

6. After the manual register and resource refresh the system replication pair is marked as in sync (SOK).

7. The cluster "failed actions" are cleaned up after following the recovery procedure.

10.1.2 Test: Stop Primary Database on Site B (Node 2) #

 

Example 17: Test STOP_PRIMARY_DB_SITE_B #

 

Component:

Primary Database

Description:

The primary HANA database is stopped during normal cluster operation.

Test Procedure: #

 

1. Stop the database gracefully as <sid>adm.

   suse02# HDB stop

Recovery Procedure: #

 

1. Manually register the old primary (on node 2) with the new primary after takeover (on node 1) as <sid>adm.

   suse02# hdbnsutil -sr_register --remoteHost=suse01 --remoteInstance=10 \
                  --replicationMode=sync --operationMode=logreplay \
                  --name=ROT

2. Restart the HANA database (now secondary) on node 2 as root.

   suse02# crm resource refresh rsc_SAPHana_HA1_HDB10 suse02

Expected: #

 

1. The cluster detects the stopped primary HANA database (on node 2) and marks the resource failed.

2. The cluster promotes the secondary HANA database (on node 1) to take over as primary.

3. The cluster migrates the IP address to the new primary (on node 1).

4. After some time the cluster shows the sync_state of the stopped primary (on node 2) as SFAIL.

5. Because AUTOMATED_REGISTER="false" the cluster does not restart the failed HANA database or register it against the new primary.

6. After the manual register and resource refresh the system replication pair is marked as in sync (SOK).

7. The cluster "failed actions" are cleaned up after following the recovery procedure.

10.1.3 Test: Crash Primary Database on Site A (Node 1) #

 

Example 18: Test CRASH_PRIMARY_DB_SITE_A #

 

Component:

Primary Database

Description:

Simulate a complete break-down of the primary database system.

Test Procedure: #

 

1. Kill the primary database system using signals as <sid>adm.

   suse01# HDB kill-9

Recovery Procedure: #

 

1. Manually register the old primary (on node 1) with the new primary after takeover (on node 2) as <sid>adm.

   suse01# hdbnsutil -sr_register --remoteHost=suse02 --remoteInstance=10 \
                  --replicationMode=sync  --operationMode=logreplay \
                  --name=WDF

2. Restart the HANA database (now secondary) on node 1 as root.

   suse01# crm resource refresh rsc_SAPHana_HA1_HDB10 suse01

Expected: #

 

1. The cluster detects the stopped primary HANA database (on node 1) and marks the resource failed.

2. The cluster promotes the secondary HANA database (on node 2) to take over as primary.

3. The cluster migrates the IP address to the new primary (on node 2).

4. After some time the cluster shows the sync_state of the stopped primary (on node 1) as SFAIL.

5. Because AUTOMATED_REGISTER="false" the cluster does not restart the failed HANA database or register it against the new primary.

6. After the manual register and resource refresh the system replication pair is marked as in sync (SOK).

7. The cluster "failed actions" are cleaned up after following the recovery procedure.

10.1.4 Test: Crash Primary Database on Site B (Node 2) #

 

Example 19: Test CRASH_PRIMARY_DB_SITE_B #

 

Component:

Primary Database

Description:

Simulate a complete break-down of the primary database system.

Test Procedure: #

 

1. Kill the primary database system using signals as <sid>adm.

   suse02# HDB kill-9

Recovery Procedure: #

 

1. Manually register the old primary (on node 2) with the new primary after takeover (on node 1) as <sid>adm.

   suse02# hdbnsutil -sr_register --remoteHost=suse01 --remoteInstance=10 \
                  --replicationMode=sync  --operationMode=logreplay \
                  --name=ROT

2. Restart the HANA database (now secondary) on node 2 as root.

   suse02# crm resource refresh rsc_SAPHana_HA1_HDB10 suse02

Expected: #

 

1. The cluster detects the stopped primary HANA database (on node 2) and marks the resource failed.

2. The cluster promotes the secondary HANA database (on node 1) to take over as primary.

3. The cluster migrates the IP address to the new primary (on node 1).

4. After some time the cluster shows the sync_state of the stopped primary (on node 2) as SFAIL.

5. Because AUTOMATED_REGISTER="false" the cluster does not restart the failed HANA database or register it against the new primary.

6. After the manual register and resource refresh the system replication pair is marked as in sync (SOK).

7. The cluster "failed actions" are cleaned up after following the recovery procedure.

10.1.5 Test: Crash Primary Node on Site A (Node 1) #

 

Example 20: Test CRASH_PRIMARY_NODE_SITE_A #

 

Component:

Cluster node of primary site

Description:

Simulate a crash of the primary site node running the primary HANA database.

Test Procedure: #

 

1. Crash the primary node by sending a 'fast-reboot' system request.

   suse01# echo 'b' > /proc/sysrq-trigger

Recovery Procedure: #

 

1. If SBD fencing is used, pacemaker will not automatically restart after being fenced. In this case clear the fencing flag on all SBD devices and subsequently start pacemaker.

   suse01# sbd -d /dev/disk/by-id/SBDA message suse01 clear
   suse01# sbd -d /dev/disk/by-id/SBDB message suse01 clear
   ...

2. Start the cluster framework

   suse01# systemctl start pacemaker

3. Manually register the old primary (on node 1) with the new primary after takeover (on node 2) as <sid>adm.

   suse01# hdbnsutil -sr_register --remoteHost=suse02 --remoteInstance=10 \
                  --replicationMode=sync  --operationMode=logreplay \
                  --name=WDF

4. Restart the HANA database (now secondary) on node 1 as root.

   suse01# crm resource refresh rsc_SAPHana_HA1_HDB10 suse01

Expected: #

 

1. The cluster detects the failed node (node 1) and declares it UNCLEAN and sets the secondary node (node 2) to status "partition with quorum".

2. The cluster fences the failed node (node 1).

3. The cluster declares the failed node (node 1) OFFLINE.

4. The cluster promotes the secondary HANA database (on node 2) to take over as primary.

5. The cluster migrates the IP address to the new primary (on node 2).

6. After some time the cluster shows the sync_state of the stopped primary (on node 2) as SFAIL.

7. If SBD fencing is used, then the manual recovery procedure will be used to clear the fencing flag and restart pacemaker on the node.

8. Because AUTOMATED_REGISTER="false" the cluster does not restart the failed HANA database or register it against the new primary.

9. After the manual register and resource refresh the system replication pair is marked as in sync (SOK).

10. The cluster "failed actions" are cleaned up after following the recovery procedure.

10.1.6 Test: Crash Primary Node on Site B (Node 2) #

 

Example 21: Test CRASH_PRIMARY_NODE_SITE_B #

 

Component:

Cluster node of secondary site

Description:

Simulate a crash of the secondary site node running the primary HANA database.

Test Procedure: #

 

1. Crash the secondary node by sending a 'fast-reboot' system request.

   suse02# echo 'b' > /proc/sysrq-trigger

Recovery Procedure: #

 

1. If SBD fencing is used, pacemaker will not automatically restart after being fenced. In this case clear the fencing flag on all SBD devices and subsequently start pacemaker.

   suse02# sbd -d /dev/disk/by-id/SBDA message suse02 clear
   suse02# sbd -d /dev/disk/by-id/SBDB message suse02 clear
   ...

2. Start the cluster Framework

   suse02# systemctl start pacemaker

3. Manually register the old primary (on node 2) with the new primary after takeover (on node 1) as <sid>adm.

   suse02# hdbnsutil -sr_register --remoteHost=suse01 --remoteInstance=10 \
                  --replicationMode=sync  --operationMode=logreplay \
                  --name=ROT

4. Restart the HANA database (now secondary) on node 2 as root.

   suse02# crm resource refresh rsc_SAPHana_HA1_HDB10 suse02

Expected: #

 

1. The cluster detects the failed secondary node (node 2) and declares it UNCLEAN and sets the primary node (node 1) to status "partition with quorum".

2. The cluster fences the failed secondary node (node 2).

3. The cluster declares the failed secondary node (node 2) OFFLINE.

4. The cluster promotes the secondary HANA database (on node 1) to take over as primary.

5. The cluster migrates the IP address to the new primary (on node 1).

6. After some time the cluster shows the sync_state of the stopped secondary (on node 2) as SFAIL.

7. If SBD fencing is used, then the manual recovery procedure will be used to clear the fencing flag and restart pacemaker on the node.

8. Because AUTOMATED_REGISTER="false" the cluster does not restart the failed HANA database or register it against the new primary.

9. After the manual register and resource refresh the system replication pair is marked as in sync (SOK).

10. The cluster "failed actions" are cleaned up after following the recovery procedure.

10.1.7 Test: Stop the Secondary Database on Site B (Node 2) #

 

Example 22: Test STOP_SECONDARY_DB_SITE_B #

 

Component:

Secondary HANA database

Description:

The secondary HANA database is stopped during normal cluster operation.

Test Procedure: #

 

1. Stop the secondary HANA database gracefully as <sid>adm.

   suse02# HDB stop

Recovery Procedure: #

 

1. Refresh the failed resource status of the secondary HANA database (on node 2) as root.

   suse02# crm resource refresh rsc_SAPHana_HA1_HDB10 suse02

Expected: #

 

1. The cluster detects the stopped secondary database (on node 2) and marks the resource failed.

2. The cluster detects the broken system replication and marks it as failed (SFAIL).

3. The cluster restarts the secondary HANA database on the same node (node 2).

4. The cluster detects that the system replication is in sync again and marks it as ok (SOK).

5. The cluster "failed actions" are cleaned up after following the recovery procedure.

10.1.8 Test: Crash the Secondary Database on Site B (Node 2) #

 

Example 23: Test CRASH_SECONDARY_DB_SITE_B #

 

Component:

Secondary HANA database

Description:

Simulate a complete break-down of the secondary database system.

Test Procedure: #

 

1. Kill the secondary database system using signals as <sid>adm.

   suse02# HDB kill-9

Recovery Procedure: #

 

1. Clean up the failed resource status of the secondary HANA database (on node 2) as root.

   suse02# crm resource refresh rsc_SAPHana_HA1_HDB10 suse02

Expected: #

 

1. The cluster detects the stopped secondary database (on node 2) and marks the resource failed.

2. The cluster detects the broken system replication and marks it as failed (SFAIL).

3. The cluster restarts the secondary HANA database on the same node (node 2).

4. The cluster detects that the system replication is in sync again and marks it as ok (SOK).

5. The cluster "failed actions" are cleaned up after following the recovery procedure.

10.1.9 Test: Crash the Secondary Node on Site B (Node2) #

 

Example 24: Test CRASH_SECONDARY_NODE_SITE_B #

 

Component:

Cluster node of secondary site

Description:

Simulate a crash of the secondary site node running the secondary HANA database.

Test Procedure: #

 

1. Crash the secondary node by sending a 'fast-reboot' system request.

   suse02# echo 'b' > /proc/sysrq-trigger

Recovery Procedure: #

 

1. If SBD fencing is used, pacemaker will not automatically restart after being fenced. In this case clear the fencing flag on all SBD devices and subsequently start pacemaker.

   suse02# sbd -d /dev/disk/by-id/SBDA message suse02 clear
   suse02# sbd -d /dev/disk/by-id/SBDB message suse02 clear
   ...

2. Start the cluster framework.

   suse02# systemctl start pacemaker

Expected: #

 

1. The cluster detects the failed secondary node (node 2) and declares it UNCLEAN and sets the primary node (node 1) to status "partition with quorum".

2. The cluster fences the failed secondary node (node 2).

3. The cluster declares the failed secondary node (node 2) OFFLINE.

4. After some time the cluster shows the sync_state of the stopped secondary (on node 2) as SFAIL.

5. If SBD fencing is used, then the manual recovery procedure will be used to clear the fencing flag and restart pacemaker on the node.

6. When the fenced node (node 2) rejoins the cluster the former secondary HANA database is started automatically.

7. The cluster detects that the system replication is in sync again and marks it as ok (SOK).

10.1.10 Test: Failure of Replication LAN #

 

Example 25: Test FAIL_NETWORK_SR #

 

Component:

Replication LAN

Description:

Loss of replication LAN connectivity between the primary and secondary node.

Test Procedure: #

 

1. Break the connection between the cluster nodes on the replication LAN.

Recovery Procedure: #

 

1. Re-establish the connection between the cluster nodes on the replication LAN.

Expected: #

 

1. After some time the cluster shows the sync_state of the secondary (on node 2) as SFAIL.

2. The primary HANA database (node 1) "HDBSettings.sh systemReplicationStatus.py" shows "CONNECTION TIMEOUT" and the secondary HANA database (node 2) is not able to reach the primary database (node 1).

3. The primary HANA database continues to operate as “normal”, but no system replication takes place and is therefore no longer a valid take over destination.

4. When the LAN connection is re-established, HDB automatically detects connectivity between the HANA databases and restarts the system replication process

5. The cluster detects that the system replication is in sync again and marks it as ok (SOK).

10.2 Test Cases for Full Automation #

 

In the following test descriptions we assume PREFER_SITE_TAKEOVER="true" and AUTOMATED_REGISTER="true".

Note

The following tests are designed to be run in sequence and depend on the exit state of the proceeding tests.

10.2.1 Test: Stop Primary Database on Site A #

 

Example 26: Test STOP_PRIMARY_DB_SITE_A #

 

Component: #

 

• Primary Database

Description: #

 

• The primary HANA database is stopped during normal cluster operation.

Test Procedure: #

 

• Stop the primary HANA database gracefully as <sid>adm.

suse01# HDB stop

Recovery Procedure: #

 

1. Not needed, everything is automated

2. Refresh the cluster resources on node 1 as root.

suse01# crm resource refresh rsc_SAPHana_HA1_HDB10 suse01

Expected: #

 

1. The cluster detects the stopped primary HANA database (on node 1) and marks the resource failed.

2. The cluster promotes the secondary HANA database (on node 2) to take over as primary.

3. The cluster migrates the IP address to the new primary (on node 2).

4. After some time the cluster shows the sync_state of the stopped primary (on node 1) as SFAIL.

5. Because AUTOMATED_REGISTER="true" the cluster does restart the failed HANA database and register it against the new primary.

6. After the automated register and resource refresh the system replication pair is marked as in sync (SOK).

7. The cluster "failed actions" are cleaned up after following the recovery procedure.

10.2.2 Test: Crash the Primary Node on Site B (Node 2) #

 

Example 27: Test CRASH_PRIMARY_NODE_SITE_B #

 

Component: #

 

• Cluster node of site B

Description: #

 

• Simulate a crash of the site B node running the primary HANA database.

Test Procedure: #

 

• Crash the secondary node by sending a 'fast-reboot' system request.

suse02# echo 'b' > /proc/sysrq-trigger

Recovery Procedure: #

 

• If SBD fencing is used, pacemaker will not automatically restart after being fenced. In this case clear the fencing flag on all SBD devices and subsequently start pacemaker.

suse02# sbd -d /dev/disk/by-id/SBDA message suse02 clear
suse02# sbd -d /dev/disk/by-id/SBDB message suse02 clear
...

• Start the cluster framework.

suse02# systemctl start pacemaker

• Refresh the cluster resources on node 2 as root.

suse02# crm resource refresh rsc_SAPHana_HA1_HDB10 suse02

Expected: #

 

1. The cluster detects the failed primary node (node 2) and declares it UNCLEAN and sets the primary node (node 2) to status "partition with quorum".

2. The cluster fences the failed primary node (node 2).

3. The cluster declares the failed primary node (node 2) OFFLINE.

4. The cluster promotes the secondary HANA database (on node 1) to take over as primary.

5. The cluster migrates the IP address to the new primary (on node 1).

6. After some time the cluster shows the sync_state of the stopped secondary (on node 2) as SFAIL.

7. If SBD fencing is used, then the manual recovery procedure will be used to clear the fencing flag and restart pacemaker on the node.

8. When the fenced node (node 2) rejoins the cluster the former primary became a secondary.

9. Because AUTOMATED_REGISTER="true" the cluster does restart the failed HANA database and register it against the new primary.

10. The cluster detects that the system replication is in sync again and marks it as ok (SOK).

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