You must check that the other databases are running and the system replication is working properly. Please refer to:

You can discover the primary HANA instance with:

clusternode1:rh2adm> hdbnsutil -sr_state | egrep -e "primary masters|^mode"
mode: primary

Before you are able to register a new secondary HANA instance, the database keys of the primary HANA instance need to be copied to the new additional HANA replication site. In our example, the hostname of the third site is remotehost3.

For example, on the primary node clusternode1, run:

clusternode1:rh2adm> scp -rp
/usr/sap/${SAPSYSTEMNAME}/SYS/global/security/rsecssfs/data/SSFS_${SAPSYSTEMNAME}.DAT  remotehost3:/usr/sap/${SAPSYSTEMNAME}/SYS/global/security/rsecssfs/data/SSFS_${SAPSYSTEMNAME}.DAT
clusternode1:rh2adm> scp -rp
/usr/sap/${SAPSYSTEMNAME}/SYS/global/security/rsecssfs/key/SSFS_${SAPSYSTEMNAME}.KEY remotehost3:/usr/sap/${SAPSYSTEMNAME}/SYS/global/security/rsecssfs/key/SSFS_${SAPSYSTEMNAME}.KEY

You need to know the name of the node that is running the primary database.
To monitor the registration, you can run the following command in a separate terminal on the primary node:

clusternode1:rh2adm> watch python
/usr/sap/${SAPSYSTEMNAME}/HDB${TINSTANCE}/python_support/systemReplicationStatus.py

This will show you the progress and any errors if they occur.

To register the HANA instance on the third site (DC3) as an additional secondary SAP HANA instance, run the following command on the third site host remotehost3:

remotehost3:rh2adm> hdbnsutil -sr_register --name=DC3
--remoteHost=clusternode1 --remoteInstance=${TINSTANCE}
--replicationMode=async --operationMode=logreplay --online

In this example, DC3 is the name of the third site, clusternode1 is the name of the primary node.

If the database instance is already running, you don’t have to stop it, you can use the option --online, which will register the instance while it is online. The necessary restart (stop and start) of the instance will then be initiated by hdbnsutil itself.

If the HANA instance is offline, you have to start it after the third node is registered. You can find additional information in SAP HANA System Replication.

We are using a SAP HANA System Replication option called register_secondaries_on_takeover = true. This will automatically re-register with the new primary site in case of a failover between the previous primary site and the other secondary site. This option must be added to the global.ini file on all potential primary sites.

All HANA instances should have this entry in their global.ini:

[system_replication]
register_secondaries_on_takeover = true

The following two chapters describe the global.ini configuration in detail.

The option register_secondaries_on_takeover = true needs to be added to the [system_replication] section in global.ini of the SAP HANA nodes of site 1 and site 2, which are managed by the pacemaker cluster. Please edit the file global.ini always on the respective node, and do not copy the file from another node.

Edit the global.ini as the rh2adm user:

clusternode1:rh2adm> vim
/usr/sap/${SAPSYSTEMNAME}/SYS/global/hdb/custom/config/global.ini

Example:

# global.ini last modified 2023-07-14 16:31:14.120444 by hdbnsutil -sr_register --remoteHost=hana07 --remoteInstance=02 --replicationMode=syncmem --operationMode=logreplay --name=DC2
[multidb]
mode = multidb
database_isolation = low
singletenant = yes

[ha_dr_provider_SAPHanaSR]
provider = SAPHanaSR
path = /hana/shared/myHooks
execution_order = 1

[persistence]
basepath_datavolumes = /hana/data/RH2
basepath_logvolumes = /hana/log/RH2
log_mode = normal
enable_auto_log_backup = true

[system_replication]
register_secondaries_on_takeover = true
timetravel_logreplay_mode = auto
operation_mode = logreplay
mode = primary
actual_mode = syncmem
site_id = 1
site_name = DC2

[system_replication_site_masters]
2 = clusternode1:30201

[trace]
ha_dr_saphanasr = info

This option is active as soon as the SAP HANA database instance is started.

Edit the global.ini as a <sid>adm user:

% vim /usr/sap/${SAPSYSTEMNAME}/SYS/global/hdb/custom/config/global.ini

On remotehost3, the ha_dr_provider_SAPHanaSR section is not used.

Example of global.ini on remotehost3:

# global.ini last modified 2023-06-22 17:22:54.154508 by hdbnameserver
[multidb]
mode = multidb
database_isolation = low
singletenant = yes

[persistence]
basepath_datavolumes = /hana/data/RH2
basepath_logvolumes = /hana/log/RH2
log_mode = normal
enable_auto_log_backup = true

[system_replication]
operation_mode = logreplay
register_secondaries_on_takeover = true
reconnect_time_interval = 5
timetravel_logreplay_mode = auto
site_id = 3
mode = syncmem
actual_mode = syncmem
site_name = DC3

[system_replication_site_masters]
2 = clusternode1:30201

After the installation, you have to check if all HANA instances are up and running and that HANA System Replication is working between them. The easiest way is to check the systemReplicationStatus, as described in more detail in Check the System Replication status. Please also refer to the Check Database for further information.

For HANA System Replication to work correctly, please ensure that the “log_mode” parameter is set to “normal”. Please refer to Checking the log_mode of the SAP HANA database for more information.

To verify that the setup is working as expected, please run the Test cases as described in the following chapter.

You need to discover the primary node to monitor a failover or run certain commands that only provide information about the replication status when executed on the primary node.

To discover the primary node, you can run the following commands as the <sid>adm user:

clusternode1:rh2adm> watch -n 5 'hdbnsutil -sr_stateConfiguration | egrep -e "primary masters|^mode"'

Output example, when clusternode2 is the primary database:

mode: syncmem
primary masters: clusternode2

A second way to identify the primary node is to run the following command as root on a cluster node:

# watch -n 5 'pcs status --full'

Output on the node that runs the primary database is:

mode: primary

The replication status shows the relationship between primary and secondary database nodes and the current status of the replication.

To discover the replication status, you can run as the <sid>adm user:

clusternode1:rh2adm> hdbnsutil -sr_stateConfiguration

If you want to permanently monitor changes in the system replication status, please run the following command:

clusternode1:rh2adm> watch -n 5 'python
/usr/sap/${SAPSYSTEMNAME}/HDB${TINSTANCE}/exe/python_support/systemReplicationStatus.py ; echo Status $?'

This example repeatedly captures the replication status and also determines the current return code.
As long as the return code (status) is 15, the replication status is fine. The other return codes are:

If you register a new secondary, you can run it in a separate window on the primary node, and you will see the progress of the replication. If you want to monitor a failover, you can run it in parallel on the old primary as well as on the new primary database server. For more information, please read Check SAP HANA System Replication Status.

Pacemaker is writing a lot of information into the /var/log/messages file. During a failover, a huge number of messages are written into this message file. To be able to follow only the important messages depending on the SAP HANA resource agent, it is useful to filter the detailed activities of the pacemaker SAP resources. It is enough to check the message file on a single cluster node.

For example, you can use this alias:

# alias tmsl='tail -1000f /var/log/messages | egrep -s "Setting master-rsc_SAPHana_${SAPSYSTEMNAME}_HDB${TINSTANCE}|sr_register|WAITING4LPA|PROMOTED|DEMOTED|UNDEFINED|master_walk|SWAIT|WaitforStopped|FAILED|LPT"'

Run this alias in a separate window to monitor the progress of the test. Please also check the example Monitor failover and sync state.

There are several ways to check the cluster status.

The pcs status --full command will give you all the necessary information. To monitor changes, you can run this command together with watch.

# pcs status --full

If you want to see changes, you can run, in a separate window, the command watch:

# watch pcs status --full

An output example and further options can be found in Check cluster status.

To ensure that your environment is ready to run the next test, leftovers from previous tests need to be fixed or removed.

This is also useful if you want to check if there is an issue in an existing environment. For more information, please refer to Useful commands.

The installation of the third site is similar to the installation of the second site. The installation can be done with hdblcm as user root. To ensure that nothing is installed before, run hdbuninst to check if SAP HANA is not already installed on this node.

Example output of HANA uninstallation:

[root@remotehost3]# cd /software/DATA_UNITS/HDB_SERVER_LINUX_X86_64
root@DC3/software/DATA_UNITS/HDB_SERVER_LINUX_X86_64# ./hdbuninst
Option 0 will remove an already existing HANA Installation
No SAP HANA Installation found is the expected answer

Example output of HANA installation on DC3:

----[root@remotehost3]# cd /software/DATA_UNITS/HDB_SERVER_LINUX_X86_64
# ./hdbuninst
Option 0 will remove an already existing HANA Installation
No SAP HANA Installation found is the expected answer
----
Example output of HANA installation:
[source,text]
----
[root@remotehost3]# ./hdblcm
1 install
2 server
/hana/shared is default directory
Enter Local Hostname [remotehost3]: use the default name
additional hosts only during Scale-Out Installation y default is n
ENTER SAP HANA System ID: RH2
Enter Instance Number [02]:
Enter Local Host Worker Group [default]:
Select System Usage / Enter Index [4]:
Choose encryption
Enter Location of Data Volumes [/hana/data/RH2]:
Enter Location of Log Volumes [/hana/log/RH2]:
Restrict maximum memory allocation? [n]:
Enter Certificate Host Name
Enter System Administrator (rh2adm) Password: <Y0urPasswd>
Confirm System Administrator (rh2adm) Password: <Y0urPasswd>
Enter System Administrator Home Directory [/usr/sap/RH2/home]:
Enter System Administrator Login Shell [/bin/sh]:
Enter System Administrator User ID [1000]:
Enter System Database User (SYSTEM) Password: <Y0urPasswd>
Confirm System Database User (SYSTEM) Password: <Y0urPasswd>
Restart system after machine reboot? [n]:
----

Before the installation starts, a summary is listed:

SAP HANA Database System Installation
   Installation Parameters
      Remote Execution: ssh
      Database Isolation: low
      Install Execution Mode: standard
      Installation Path: /hana/shared
      Local Host Name: dc3host
      SAP HANA System ID: RH2
      Instance Number: 02
      Local Host Worker Group: default
      System Usage: custom
      Location of Data Volumes: /hana/data/RH2
      Location of Log Volumes: /hana/log/RH2
      SAP HANA Database secure store: ssfs
      Certificate Host Names: remotehost3 -> remotehost3      System Administrator Home Directory: /usr/sap/RH2/home
      System Administrator Login Shell: /bin/sh
      System Administrator User ID: 1000
      ID of User Group (sapsys): 1010
   Software Components
      SAP HANA Database
         Install version 2.00.052.00.1599235305
         Location: /software/DATA_UNITS/HDB_SERVER_LINUX_X86_64/server
      SAP HANA Local Secure Store
         Do not install
      SAP HANA AFL (incl.PAL,BFL,OFL)
         Do not install
      SAP HANA EML AFL
         Do not install
      SAP HANA EPM-MDS
         Do not install
      SAP HANA Database Client
         Do not install
      SAP HANA Studio
         Do not install
      SAP HANA Smart Data Access
         Do not install
      SAP HANA XS Advanced Runtime
         Do not install
   Log File Locations
      Log directory: /var/tmp/hdb_RH2_hdblcm_install_2021-06-09_18.48.13
      Trace location: /var/tmp/hdblcm_2021-06-09_18.48.13_31307.trc

Do you want to continue? (y/n):

Enter y to start the installation.

clusternode1:rh2adm> hdbsql -i ${TINSTANCE} -u system -p Y0urP8ssw0rd

Welcome to the SAP HANA Database interactive terminal.

Type:  \h for help with commands
       \q to quit

hdbsql RH2=> select * from M_INIFILE_CONTENTS where section='system_replication'
FILE_NAME,LAYER_NAME,TENANT_NAME,HOST,SECTION,KEY,VALUE
"global.ini","DEFAULT","","","system_replication","actual_mode","primary"
"global.ini","DEFAULT","","","system_replication","mode","primary"
"global.ini","DEFAULT","","","system_replication","operation_mode","logreplay"
"global.ini","DEFAULT","","","system_replication","register_secondaries_on_takeover
","true"
"global.ini","DEFAULT","","","system_replication","site_id","1"
"global.ini","DEFAULT","","","system_replication","site_name","DC2"
"global.ini","DEFAULT","","","system_replication","timetravel_logreplay_mode","auto
"
"global.ini","DEFAULT","","","system_replication","alternative_sources",""
"global.ini","DEFAULT","","","system_replication","datashipping_logsize_threshold",
"5368709120"
"global.ini","DEFAULT","","","system_replication","datashipping_min_time_interval",
"600"
"global.ini","DEFAULT","","","system_replication","datashipping_parallel_channels",
"4"
"global.ini","DEFAULT","","","system_replication","datashipping_parallel_processing
","true"
"global.ini","DEFAULT","","","system_replication","datashipping_snapshot_max_retent
ion_time","300"
"global.ini","DEFAULT","","","system_replication","enable_data_compression","false"
"global.ini","DEFAULT","","","system_replication","enable_full_sync","false"
"global.ini","DEFAULT","","","system_replication","enable_log_compression","false"
"global.ini","DEFAULT","","","system_replication","enable_log_retention","auto"
"global.ini","DEFAULT","","","system_replication","full_replica_on_failed_delta_syn
c_check","false"
"global.ini","DEFAULT","","","system_replication","hint_based_routing_site_name",""
"global.ini","DEFAULT","","","system_replication","keep_old_style_alert","false"
"global.ini","DEFAULT","","","system_replication","logshipping_async_buffer_size","
67108864"
"global.ini","DEFAULT","","","system_replication","logshipping_async_wait_on_buffer
_full","true"
"global.ini","DEFAULT","","","system_replication","logshipping_max_retention_size",
"1048576"
"global.ini","DEFAULT","","","system_replication","logshipping_replay_logbuffer_cac
he_size","1073741824"
"global.ini","DEFAULT","","","system_replication","logshipping_replay_push_persiste
nt_segment_count","5"
"global.ini","DEFAULT","","","system_replication","logshipping_snapshot_logsize_thr
eshold","3221225472"
"global.ini","DEFAULT","","","system_replication","logshipping_snapshot_min_time_in
terval","900"
"global.ini","DEFAULT","","","system_replication","logshipping_timeout","30"
"global.ini","DEFAULT","","","system_replication","preload_column_tables","true"
"global.ini","DEFAULT","","","system_replication","propagate_log_retention","off"
"global.ini","DEFAULT","","","system_replication","reconnect_time_interval","30"
"global.ini","DEFAULT","","","system_replication","retries_before_register_to_alter
native_source","20"
"global.ini","DEFAULT","","","system_replication","takeover_esserver_without_log_ba
ckup","false"
"global.ini","DEFAULT","","","system_replication","takeover_wait_until_esserver_res
tart","true"
"global.ini","DEFAULT","","","system_replication","timetravel_call_takeover_hooks",
"off"
"global.ini","DEFAULT","","","system_replication","timetravel_log_retention_policy"
,"none"
"global.ini","DEFAULT","","","system_replication","timetravel_max_retention_time","
0"
"global.ini","DEFAULT","","","system_replication","timetravel_snapshot_creation_int
erval","1440"
"indexserver.ini","DEFAULT","","","system_replication","logshipping_async_buffer_si
ze","268435456"
"indexserver.ini","DEFAULT","","","system_replication","logshipping_replay_logbuffe
r_cache_size","4294967296"
"indexserver.ini","DEFAULT","","","system_replication","logshipping_replay_push_per
sistent_segment_count","20"
41 rows selected (overall time 1971.958 msec; server time 31.359 msec)

Check if the database is running and discover the current primary node.

List database instances

clusternode1:rh2adm> sapcontrol -nr ${TINSTANCE} -function
GetSystemInstanceList

23.06.2023 12:08:17
GetSystemInstanceList
OK
hostname, instanceNr, httpPort, httpsPort, startPriority, features, dispstatus
node1, 2, 50213, 50214, 0.3, HDB|HDB_WORKER, GREEN

If the output is green the instance is running.

List database processes

clusternode1:rh2adm> sapcontrol -nr ${TINSTANCE} -function GetProcessList
GetProcessList
OK
name, description, dispstatus, textstatus, starttime, elapsedtime, pid
hdbdaemon, HDB Daemon, GREEN, Running, 2023 09 04 14:34:01, 18:41:33, 3788067
hdbcompileserver, HDB Compileserver, GREEN, Running, 2023 09 04 22:35:40, 10:39:54, 445299
hdbindexserver, HDB Indexserver-RH2, GREEN, Running, 2023 09 04 22:35:40, 10:39:54, 445391
hdbnameserver, HDB Nameserver, GREEN, Running, 2023 09 04 22:35:34, 10:40:00, 445178
hdbpreprocessor, HDB Preprocessor, GREEN, Running, 2023 09 04 22:35:40, 10:39:54, 445306
hdbwebdispatcher, HDB Web Dispatcher, GREEN, Running, 2023 09 04 22:35:53, 10:39:41, 445955
hdbxsengine, HDB XSEngine-RH2, GREEN, Running, 2023 09 04 22:35:40, 10:39:54, 445394

Usually, all database processes have the status GREEN.

List SAP HANA processes

clusternode1:rh2adm> HDB info
USER          PID     PPID  %CPU        VSZ        RSS COMMAND
rh2adm       1560     1559   0.0       6420       3136 watch -n 5 sapcontrol -nr 02 -functi
rh2adm       1316     1315   0.0       8884       5676 -sh
rh2adm       2549     1316   0.0       7516       4072  \_ /bin/sh /usr/sap/RH2/HDB02/HDB i
rh2adm       2579     2549   0.0      10144       3576      \_ ps fx -U rh2adm -o user:8,pi
rh2adm       2388        1   0.0     679536      55520 hdbrsutil  --start --port 30203 --vo
rh2adm       1921        1   0.0     679196      55312 hdbrsutil  --start --port 30201 --vo
rh2adm       1469        1   0.0       8852       3260 sapstart pf=/usr/sap/RH2/SYS/profile
rh2adm       1476     1469   0.7     438316      86288  \_ /usr/sap/RH2/HDB02/remotehost3/trace/
rh2adm       1501     1476  11.7    9690172    1574796      \_ hdbnameserver
rh2adm       1845     1476   0.8     410696     122988      \_ hdbcompileserver
rh2adm       1848     1476   1.0     659464     154072      \_ hdbpreprocessor
rh2adm       1899     1476  14.7    9848276    1765208      \_ hdbindexserver -port 30203
rh2adm       1902     1476   8.4    5023288    1052768      \_ hdbxsengine -port 30207
rh2adm       2265     1476   5.2    2340284     405016      \_ hdbwebdispatcher
rh2adm       1117        1   1.1     543532      30676 /usr/sap/RH2/HDB02/exe/sapstartsrv p
rh2adm       1029        1   0.0      20324      11572 /usr/lib/systemd/systemd --user
rh2adm       1030     1029   0.0      23256       3536  \_ (sd-pam)

Display SAP HANA landscape configuration

clusternode1:rh2adm>
/usr/sap/${SAPSYSTEMNAME}/HDB${TINSTANCE}/exe/Python/bin/python
/usr/sap/${SAPSYSTEMNAME}/HDB${TINSTANCE}/exe/python_support/landscapeHostConfiguration.py;echo $?
| Host   | Host   | Host   | Failover | Remove | Storage   | Storage   | Failover | Failover | NameServer | NameServer | IndexServer | IndexServer | Host   | Host   | Worker  | Worker  |
|        | Active | Status | Status   | Status | Config    | Actual    | Config   | Actual   | Config     | Actual     | Config      | Actual      | Config | Actual | Config  | Actual  |
|        |        |        |          |        | Partition | Partition | Group    | Group    | Role       | Role       | Role        | Role        | Roles  | Roles  | Groups  | Groups  |
| ------ | ------ | ------ | -------- | ------ | --------- | --------- | -------- | -------- | ---------- | ---------- | ----------- | ----------- | ------ | ------ | ------- | ------- |
| clusternode1 | yes    | ok     |          |        |         1 |         1 | default  | default  | master 1   | master     | worker      | master      | worker | worker | default | default |

overall host status: ok
4

Returncodes:

Discover primary database

clusternode1:rh2adm> hdbnsutil -sr_state | egrep -e "primary masters|^mode"

Example of check on a secondary:

clusternode1:rh2adm> hdbnsutil -sr_state | egrep -e "primary masters|^mode"
mode: syncmem
primary masters: clusternode1

Example of check on the current primary:

clusternode1:rh2adm> hdbnsutil -sr_state | egrep -e "primary masters|^mode"
mode: primary

clusternode1:rh2adm>hdbnsutil -sr_state --sapcontrol=1 |grep  site.*Mode
siteReplicationMode/DC1=primary
siteReplicationMode/DC3=async
siteReplicationMode/DC2=syncmem
siteOperationMode/DC1=primary
siteOperationMode/DC3=logreplay
siteOperationMode/DC2=logreplay

Display the database version

Example using SQL query:

hdbsql RH2=> select * from m_database
SYSTEM_ID,DATABASE_NAME,HOST,START_TIME,VERSION,USAGE
"RH2","RH2","node1","2023-06-22 15:33:05.235000000","2.00.059.02.1647435895","CUSTOM"
1 row selected (overall time 29.107 msec; server time 927 usec)

Example using systemOverview.py:

clusternode1:rh2adm> python ./systemOverview.py
| Section    | Name            | Status  | Value                                               |
| ---------- | --------------- | ------- | --------------------------------------------------- |
| System     | Instance ID     |         | RH2                                                 |
| System     | Instance Number |         | 02                                                  |
| System     | Distributed     |         | No                                                  |
| System     | Version         |         | 2.00.059.02.1647435895 (fa/hana2sp05)               |
| System     | Platform        |         | Red Hat Enterprise Linux 9.2 Beta (Plow) 9.2 (Plow) |
| Services   | All Started     | OK      | Yes                                                 |
| Services   | Min Start Time  |         | 2023-07-14 16:31:19.000                             |
| Services   | Max Start Time  |         | 2023-07-26 11:23:17.324                             |
| Memory     | Memory          | OK      | Physical 31.09 GB, Swap 10.00 GB, Used 26.38        |
| CPU        | CPU             | OK      | Available 4, Used 1.04                              |
| Disk       | Data            | OK      | Size 89.0 GB, Used 59.3 GB, Free 33 %               |
| Disk       | Log             | OK      | Size 89.0 GB, Used 59.3 GB, Free 33 %               |
| Disk       | Trace           | OK      | Size 89.0 GB, Used 59.3 GB, Free 33 %               |
| Statistics | Alerts          | WARNING | cannot check statistics w/o SQL connection          |

Option 1: HDB command

clusternode1:rh2adm> HDB help
Usage: /usr/sap/RH2/HDB02/HDB { start|stop|reconf|restart|version|info|proc|admin|kill|kill-<sig>|term }
  kill or kill-9 should never be used in a productive environment!

Option 2 (recommended): Use sapcontrol

clusternode1:rh2adm> sapcontrol -nr ${TINSTANCE} -function StartSystem HDB

03.07.2023 14:08:30
StartSystem
OK

clusternode1:rh2adm> sapcontrol -nr ${TINSTANCE} -function StopSystem HDB

03.07.2023 14:09:33
StopSystem
OK

Use the GetProcessList to monitor the starting and stopping of HANA services:

clusternode1:rh2adm> sapcontrol -nr ${TINSTANCE} -function GetProcessList

There are many ways to check the SAP HANA System Replication status:

Example of systemReplicationStatus.py output running as a monitor:

clusternode1:rh2adm> watch -n 5 "python
/usr/sap/${SAPSYSTEMNAME}/HDB{TINSTACE}/exe/python_support/systemReplicationStatus.py;echo \$?"
 concurrent-fencing: true
Every 5.0s: python systemReplicationStatus.py;echo $?                                                                                                                              hana08: Fri Jul 28 17:01:05 2023

|Database |Host   |Port  |Service Name |Volume ID |Site ID |Site Name |Secondary |Secondary |Secondary |Secondary |Secondary     |Replication |Replication |Replication    |
|         |	  |	 |             |          |        |          |Host	 |Port      |Site ID   |Site Name |Active Status |Mode        |Status	   |Status Details |
|-------- |------ |----- |------------ |--------- |------- |--------- |--------- |--------- |--------- |--------- |------------- |----------- |----------- |-------------- |
|SYSTEMDB |hana08 |30201 |nameserver   |        1 |	 1 |DC2       |hana09    |    30201 |        3 |DC3	  |YES           |SYNCMEM     |ACTIVE	   |               |
|RH2	  |hana08 |30207 |xsengine     |        2 |	 1 |DC2       |hana09    |    30207 |        3 |DC3	  |YES           |SYNCMEM     |ACTIVE	   |               |
|RH2	  |hana08 |30203 |indexserver  |        3 |	 1 |DC2       |hana09    |    30203 |        3 |DC3	  |YES           |SYNCMEM     |ACTIVE	   |               |
|SYSTEMDB |hana08 |30201 |nameserver   |        1 |	 1 |DC2       |remotehost3    |    30201 |        2 |DC1	  |YES           |SYNCMEM     |ACTIVE	   |               |
|RH2	  |hana08 |30207 |xsengine     |        2 |	 1 |DC2       |remotehost3    |    30207 |        2 |DC1	  |YES           |SYNCMEM     |ACTIVE	   |               |
|RH2	  |hana08 |30203 |indexserver  |        3 |	 1 |DC2       |remotehost3    |    30203 |        2 |DC1	  |YES           |SYNCMEM     |ACTIVE	   |               |

status system replication site "3": ACTIVE
status system replication site "2": ACTIVE
overall system replication status: ACTIVE

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

mode: PRIMARY
site id: 1
site name: DC2
15

The expected results for the return codes are:

In most cases the System Replication check will return with return code 15. Another display option is to use -t (printLandscapeTree).

Example for the output on the current primary:

clusternode1:rh2adm> python systemReplicationStatus.py -t
HANA System Replication landscape:
  DC1  ( primary )
     | --- DC3  ( syncmem )
     | --- DC2  ( syncmem )

Example of hdbnsutil -sr_state:

[root@clusternode1]# su - rh2adm
clusternode1:rh2adm> watch -n 10 hdbnsutil -sr_state
Every 10.0s: hdbnsutil -sr_state                                                                           clusternode1: Thu Jun 22 08:42:00 2023


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

online: true

mode: syncmem
operation mode: logreplay
site id: 2
site name: DC1

is source system: false
is secondary/consumer system: true
has secondaries/consumers attached: false
is a takeover active: false
is primary suspended: false
is timetravel enabled: false
replay mode: auto
active primary site: 1

primary masters: clusternode2

Host Mappings:
~~~~~~~~~~~~~~

clusternode1 -> [DC3] remotehost3
clusternode1 -> [DC1] clusternode1
clusternode1 -> [DC2] clusternode2


Site Mappings:
~~~~~~~~~~~~~~
DC2 (primary/primary)
    |---DC3 (syncmem/logreplay)
    |---DC1 (syncmem/logreplay)

Tier of DC2: 1
Tier of DC3: 2
Tier of DC1: 2

Replication mode of DC2: primary
[2] 0:ssh*

Example of sr_stateConfiguation on the primary:

clusternode1:rh2adm> hdbnsutil -sr_stateConfiguration

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

mode: primary
site id: 2
site name: DC1
done.

Example of sr_stateConfiguration on the secondary:

clusternode1:rh2adm> hdbnsutil -sr_stateConfiguration

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

mode: syncmem
site id: 1
site name: DC2
active primary site: 2

primary masters: clusternode1
done.

You can also check in the secondary database which node is the current primary. During the failover it happens to have two primary databases and this information is needed to decide which potential primary database is wrong and needs to be re-registered as secondary.

For additional information, refer to Example: Checking the Status on the Primary and Secondary Systems.

Preconditions to register a secondary database for a SAP HANA System Replication environment:

Registration example:

clusternode1:rh2adm> hdbnsutil -sr_register --remoteHost=clusternode2 --remoteInstance=${TINSTANCE} --replicationMode=syncmem --name=DC1 --online
--operationMode not set; using default from global.ini/[system_replication]/operation_mode: logreplay
adding site ...
collecting information ...
updating local ini files ...
done.

With the registration the global.ini file will be automatically updated

… from:

# global.ini last modified 2023-06-15 09:55:05.665341 by /usr/sap/RH2/HDB02/exe/hdbnsutil -initTopology --workergroup=default --set_user_system_pw
[multidb]
mode = multidb
database_isolation = low
singletenant = yes

[persistence]
basepath_datavolumes = /hana/data/RH2
basepath_logvolumes = /hana/log/RH2

… to:

# global.ini last modified 2023-06-15 11:25:44.516946 by hdbnsutil -sr_register --remoteHost=node2 --remoteInstance=02 --replicationMode=syncmem --name=DC1 --online
[multidb]
mode = multidb
database_isolation = low
singletenant = yes

[persistence]
basepath_datavolumes = /hana/data/RH2
basepath_logvolumes = /hana/log/RH2

[system_replication]
timetravel_logreplay_mode = auto
site_id = 3
mode = syncmem
actual_mode = syncmem
site_name = DC1
operation_mode = logreplay

[system_replication_site_masters]
1 = clusternode2:30201

Check the processes of an active SAP HANA database

clusternode1:rh2adm> sapcontrol -nr ${TINSTANCE} -function GetProcessList                                          clusternode1: Wed Jun  7 08:23:03 2023

07.06.2023 08:23:03
GetProcessList
OK
name, description, dispstatus, textstatus, starttime, elapsedtime, pid
hdbdaemon, HDB Daemon, GREEN, Running, 2023 06 02 16:59:42, 111:23:21, 4245
hdbcompileserver, HDB Compileserver, GREEN, Running, 2023 06 02 17:01:35, 111:21:28, 7888
hdbindexserver, HDB Indexserver-RH2, GREEN, Running, 2023 06 02 17:01:36, 111:21:27, 7941
hdbnameserver, HDB Nameserver, GREEN, Running, 2023 06 02 17:01:29, 111:21:34, 7594
hdbpreprocessor, HDB Preprocessor, GREEN, Running, 2023 06 02 17:01:35, 111:21:28, 7891
hdbwebdispatcher, HDB Web Dispatcher, GREEN, Running, 2023 06 02 17:01:42, 111:21:21, 8339
hdbxsengine, HDB XSEngine-RH2, GREEN, Running, 2023 06 02 17:01:36, 111:21:27, 7944

This will list the status of instances of a SAP HANA database. It will also show the ports. There are three different status names:

Example of an active instance:

clusternode1:rh2adm> sapcontrol -nr ${TINSTANCE} -function GetSystemInstanceList                                   clusternode1: Wed Jun  7 08:24:13 2023


07.06.2023 08:24:13
GetSystemInstanceList
OK
hostname, instanceNr, httpPort, httpsPort, startPriority, features, dispstatus
remotehost3, 2, 50213, 50214, 0.3, HDB|HDB_WORKER, GREEN

Example of a stopped instance:

clusternode1:rh2adm> sapcontrol -nr ${TINSTANCE} -function GetSystemInstanceList

22.06.2023 09:14:55
GetSystemInstanceList
OK
hostname, instanceNr, httpPort, httpsPort, startPriority, features, dispstatus
remotehost3, 2, 50213, 50214, 0.3, HDB|HDB_WORKER, GRAY

You can also use the HDB Console to display information about the database:

Example of ‘replication info’:

clusternode1:rh2adm> hdbcons -e hdbindexserver 'replication info'
hdbcons -p `pgrep hdbindex` 'replication info'
SAP HANA DB Management Client Console (type '\?' to get help for client commands)
Try to open connection to server process with PID 451925
SAP HANA DB Management Server Console (type 'help' to get help for server commands)
Executable: hdbindexserver (PID: 451925)
[OK]
--
## Start command at: 2023-06-22 09:05:25.211
listing default statistics for volume 3
System Replication Primary Information
======================================
System Replication Primary Configuration
 [system_replication] logshipping_timeout                         = 30
 [system_replication] enable_full_sync                            = false
 [system_replication] preload_column_tables                       = true
 [system_replication] ensure_backup_history                       = true
 [system_replication_communication] enable_ssl                    = off
 [system_replication] keep_old_style_alert                        = false
 [system_replication] enable_log_retention                        = auto
 [system_replication] logshipping_max_retention_size              = 1048576
 [system_replication] logshipping_async_buffer_size               = 268435456
 - lastLogPos                  : 0x4ab2700
 - lastLogPosTimestamp         : 22.06.2023-07.05.25 (1687417525193952)
 - lastConfirmedLogPos         : 0x4ab2700
 - lastConfirmedLogPosTimestamp: 22.06.2023-07.05.25 (1687417525193952)
 - lastSavepointVersion        : 1286
 - lastSavepointLogPos         : 0x4ab0602
 - lastSavepointTimestamp      : 22.06.2023-07.02.42 (1687417362853007)
 2 session registered.
Session index 0
 - SiteID              : 3
 - RemoteHost          : 192.168.5.137
Log Connection
 - ptr               : 0x00007ff04c0a1000
 - channel           : {<NetworkChannelSSLFilter>={<NetworkChannelBase>={this=140671686293528, fd=70, refCnt=2, idx=5, local=192.168.5.134/40203_tcp, remote=192.168.5.137/40406_tcp, state=Connected, pending=[r---]}}}
 - SSLActive           : false
 - mode              : syncmem
Data Connection
 - ptr               : 0x00007ff08b730000
 - channel           : {<NetworkChannelSSLFilter>={<NetworkChannelBase>={this=140671436247064, fd=68, refCnt=2, idx=6, local=192.168.5.134/40203_tcp, remote=192.168.5.137/40408_tcp, state=Connected, pending=[r---]}}}
 - SSLActive           : false
Primary Statistics
 - Creation Timestamp              : 20.06.2023-13.55.07 (1687269307772532)
 - Last Reset Timestamp            : 20.06.2023-13.55.07 (1687269307772532)
 - Statistic Reset Count           : 0
 - ReplicationMode                 : syncmem
 - OperationMode                   : logreplay
 - ReplicationStatus               : ReplicationStatus_Active
 - ReplicationStatusDetails        :
 - ReplicationFullSync             : DISABLED
 - shippedLogPos                   : 0x4ab2700
 - shippedLogPosTimestamp          : 22.06.2023-07.05.25 (1687417525193952)
 - sentLogPos                      : 0x4ab2700
 - sentLogPosTimestamp             : 22.06.2023-07.05.25 (1687417525193952)
 - sentMaxLogWriteEndPosition      : 0x4ab2700
 - sentMaxLogWriteEndPositionReqCnt: 0x1f6b8
 - shippedLogBuffersCount          : 142439
 - shippedLogBuffersSize           : 805855232 bytes
 - shippedLogBuffersSizeUsed       : 449305792 bytes (55.76clusternode1:rh2adm>)
 - shippedLogBuffersSizeNet        : 449013696 bytes (55.72clusternode1:rh2adm>)
 - shippedLogBufferDuration        : 83898615 microseconds
 - shippedLogBufferDurationMin     : 152 microseconds
 - shippedLogBufferDurationMax     : 18879 microseconds
 - shippedLogBufferDurationSend    : 7301067 microseconds
 - shippedLogBufferDurationComp    : 0 microseconds
 - shippedLogBufferThroughput      : 9709099.18 bytes/s
 - shippedLogBufferPendingDuration : 80583785 microseconds
 - shippedLogBufferRealThrougput   : 10073190.40 bytes/s
 - replayLogPos                    : 0x4ab2700
 - replayLogPosTimestamp           : 22.06.2023-07.05.25 (1687417525193952)
 - replayBacklog                   : 0 microseconds
 - replayBacklogSize               : 0 bytes
 - replayBacklogMax                : 822130896 microseconds
 - replayBacklogSizeMax            : 49455104 bytes
 - shippedSavepointVersion         : 0
 - shippedSavepointLogPos          : 0x0
 - shippedSavepointTimestamp       : not set
 - shippedFullBackupCount          : 0
 - shippedFullBackupSize           : 0 bytes
 - shippedFullBackupSizeNet        : 0 bytes (-nanclusternode1:rh2adm>)
 - shippedFullBackupDuration       : 0 microseconds
 - shippedFullBackupDurationComp   : 0 microseconds
 - shippedFullBackupThroughput     : 0.00 bytes/s
 - shippedFullBackupStreamCount     : 0
 - shippedFullBackupResumeCount     : 0
 - shippedLastFullBackupSize       : 0 bytes
 - shippedLastFullBackupSizeNet    : 0 bytes (-nanclusternode1:rh2adm>)
 - shippedLastFullBackupStart      : not set
 - shippedLastFullBackupEnd        : not set
 - shippedLastFullBackupDuration   : 0 microseconds
 - shippedLastFullBackupStreamCount : 0
 - shippedLastFullBackupResumeCount : 0
 - shippedDeltaBackupCount         : 0
 - shippedDeltaBackupSize          : 0 bytes
 - shippedDeltaBackupSizeNet       : 0 bytes (-nanclusternode1:rh2adm>)
 - shippedDeltaBackupDuration      : 0 microseconds
 - shippedDeltaBackupDurationComp  : 0 microseconds
 - shippedDeltaBackupThroughput    : 0.00 bytes/s
 - shippedDeltaBackupStreamCount   : 0
 - shippedDeltaBackupResumeCount   : 0
 - shippedLastDeltaBackupSize      : 0 bytes
 - shippedLastDeltaBackupSizeNet   : 0 bytes (-nanclusternode1:rh2adm>)
 - shippedLastDeltaBackupStart     : not set
 - shippedLastDeltaBackupEnd       : not set
 - shippedLastDeltaBackupDuration  : 0 microseconds
 - shippedLastDeltaBackupStreamCount : 0
 - shippedLastDeltaBackupResumeCount : 0
 - currentTransferType             : None
 - currentTransferSize             : 0 bytes
 - currentTransferPosition         : 0 bytes (0clusternode1:rh2adm>)
 - currentTransferStartTime        : not set
 - currentTransferThroughput       : 0.00 MB/s
 - currentTransferStreamCount      : 0
 - currentTransferResumeCount      : 0
 - currentTransferResumeStartTime  : not set
 - Secondary sync'ed via Log Count : 1
 - syncLogCount                    : 3
 - syncLogSize                     : 62840832 bytes
 - backupHistoryComplete           : 1
 - backupLogPosition               : 0x4a99980
 - backupLogPositionUpdTimestamp   : 22.06.2023-06.56.27 (0x5feb26227e7af)
 - shippedMissingLogCount          : 0
 - shippedMissingLogSize           : 0 bytes
 - backlogSize                     : 0 bytes
 - backlogTime                     : 0 microseconds
 - backlogSizeMax                  : 0 bytes
 - backlogTimeMax                  : 0 microseconds
 - Secondary Log Connect time      : 20.06.2023-13.55.31 (1687269331361049)
 - Secondary Data Connect time     : 20.06.2023-13.55.33 (1687269333768341)
 - Secondary Log Close time        : not set
 - Secondary Data Close time       : 20.06.2023-13.55.31 (1687269331290050)
 - Secondary Log Reconnect Count   : 0
 - Secondary Log Failover Count    : 0
 - Secondary Data Reconnect Count  : 1
 - Secondary Data Failover Count   : 0
----------------------------------------------------------------
Session index 1
 - SiteID              : 2
 - RemoteHost          : 192.168.5.133
Log Connection
 - ptr               : 0x00007ff0963e4000
 - channel           : {<NetworkChannelSSLFilter>={<NetworkChannelBase>={this=140671506282520, fd=74, refCnt=2, idx=0, local=192.168.5.134/40203_tcp, remote=192.168.5.133/40404_tcp, state=Connected, pending=[r---]}}}
 - SSLActive           : false
 - mode              : syncmem
Data Connection
 - ptr               : 0x00007ff072c04000
 - channel           : {<NetworkChannelSSLFilter>={<NetworkChannelBase>={this=140671463146520, fd=75, refCnt=2, idx=1, local=192.168.5.134/40203_tcp, remote=192.168.5.133/40406_tcp, state=Connected, pending=[r---]}}}
 - SSLActive           : false
Primary Statistics
 - Creation Timestamp              : 20.06.2023-13.55.49 (1687269349892111)
 - Last Reset Timestamp            : 20.06.2023-13.55.49 (1687269349892111)
 - Statistic Reset Count           : 0
 - ReplicationMode                 : syncmem
 - OperationMode                   : logreplay
 - ReplicationStatus               : ReplicationStatus_Active
 - ReplicationStatusDetails        :
 - ReplicationFullSync             : DISABLED
 - shippedLogPos                   : 0x4ab2700
 - shippedLogPosTimestamp          : 22.06.2023-07.05.25 (1687417525193952)
 - sentLogPos                      : 0x4ab2700
 - sentLogPosTimestamp             : 22.06.2023-07.05.25 (1687417525193952)
 - sentMaxLogWriteEndPosition      : 0x4ab2700
 - sentMaxLogWriteEndPositionReqCnt: 0x1f377
 - shippedLogBuffersCount          : 142326
 - shippedLogBuffersSize           : 793939968 bytes
 - shippedLogBuffersSizeUsed       : 437675200 bytes (55.13clusternode1:rh2adm>)
 - shippedLogBuffersSizeNet        : 437565760 bytes (55.11clusternode1:rh2adm>)
 - shippedLogBufferDuration        : 76954026 microseconds
 - shippedLogBufferDurationMin     : 115 microseconds
 - shippedLogBufferDurationMax     : 19285 microseconds
 - shippedLogBufferDurationSend    : 2951495 microseconds
 - shippedLogBufferDurationComp    : 0 microseconds
 - shippedLogBufferThroughput      : 10446578.53 bytes/s
 - shippedLogBufferPendingDuration : 73848247 microseconds
 - shippedLogBufferRealThrougput   : 10875889.97 bytes/s
 - replayLogPos                    : 0x4ab2700
 - replayLogPosTimestamp           : 22.06.2023-07.05.25 (1687417525193952)
 - replayBacklog                   : 0 microseconds
 - replayBacklogSize               : 0 bytes
 - replayBacklogMax                : 113119944 microseconds
 - replayBacklogSizeMax            : 30171136 bytes
 - shippedSavepointVersion         : 0
 - shippedSavepointLogPos          : 0x0
 - shippedSavepointTimestamp       : not set
 - shippedFullBackupCount          : 0
 - shippedFullBackupSize           : 0 bytes
 - shippedFullBackupSizeNet        : 0 bytes (-nanclusternode1:rh2adm>)
 - shippedFullBackupDuration       : 0 microseconds
 - shippedFullBackupDurationComp   : 0 microseconds
 - shippedFullBackupThroughput     : 0.00 bytes/s
 - shippedFullBackupStreamCount     : 0
 - shippedFullBackupResumeCount     : 0
 - shippedLastFullBackupSize       : 0 bytes
 - shippedLastFullBackupSizeNet    : 0 bytes (-nanclusternode1:rh2adm>)
 - shippedLastFullBackupStart      : not set
 - shippedLastFullBackupEnd        : not set
 - shippedLastFullBackupDuration   : 0 microseconds
 - shippedLastFullBackupStreamCount : 0
 - shippedLastFullBackupResumeCount : 0
 - shippedDeltaBackupCount         : 0
 - shippedDeltaBackupSize          : 0 bytes
 - shippedDeltaBackupSizeNet       : 0 bytes (-nanclusternode1:rh2adm>)
 - shippedDeltaBackupDuration      : 0 microseconds
 - shippedDeltaBackupDurationComp  : 0 microseconds
 - shippedDeltaBackupThroughput    : 0.00 bytes/s
 - shippedDeltaBackupStreamCount   : 0
 - shippedDeltaBackupResumeCount   : 0
 - shippedLastDeltaBackupSize      : 0 bytes
 - shippedLastDeltaBackupSizeNet   : 0 bytes (-nanclusternode1:rh2adm>)
 - shippedLastDeltaBackupStart     : not set
 - shippedLastDeltaBackupEnd       : not set
 - shippedLastDeltaBackupDuration  : 0 microseconds
 - shippedLastDeltaBackupStreamCount : 0
 - shippedLastDeltaBackupResumeCount : 0
 - currentTransferType             : None
 - currentTransferSize             : 0 bytes
 - currentTransferPosition         : 0 bytes (0clusternode1:rh2adm>)
 - currentTransferStartTime        : not set
 - currentTransferThroughput       : 0.00 MB/s
 - currentTransferStreamCount      : 0
 - currentTransferResumeCount      : 0
 - currentTransferResumeStartTime  : not set
 - Secondary sync'ed via Log Count : 1
 - syncLogCount                    : 3
 - syncLogSize                     : 61341696 bytes
 - backupHistoryComplete           : 1
 - backupLogPosition               : 0x4a99980
 - backupLogPositionUpdTimestamp   : 22.06.2023-06.56.27 (0x5feb26227e670)
 - shippedMissingLogCount          : 0
 - shippedMissingLogSize           : 0 bytes
 - backlogSize                     : 0 bytes
 - backlogTime                     : 0 microseconds
 - backlogSizeMax                  : 0 bytes
 - backlogTimeMax                  : 0 microseconds
 - Secondary Log Connect time      : 20.06.2023-13.56.21 (1687269381053599)
 - Secondary Data Connect time     : 20.06.2023-13.56.27 (1687269387399610)
 - Secondary Log Close time        : not set
 - Secondary Data Close time       : 20.06.2023-13.56.21 (1687269381017244)
 - Secondary Log Reconnect Count   : 0
 - Secondary Log Failover Count    : 0
 - Secondary Data Reconnect Count  : 1
 - Secondary Data Failover Count   : 0
----------------------------------------------------------------
[OK]
## Finish command at: 2023-06-22 09:05:25.212 command took: 572.000 usec
--
[EXIT]
--
[BYE]

Example of help:

clusternode1:rh2adm> hdbcons  -e hdbindexserver help
SAP HANA DB Management Client Console (type '\?' to get help for client commands)
Try to open connection to server process with PID 451925
SAP HANA DB Management Server Console (type 'help' to get help for server commands)
Executable: hdbindexserver (PID: 451925)
[OK]
--
## Start command at: 2023-06-22 09:07:16.784
Synopsis:
help [<command name>]: Print command help
   - <command name> - Command name for which to display help
Available commands:
ae_tableload - Handle loading of column store tables and columns
all - Print help and other info for all hdbcons commands
authentication - Authentication management.
binarysemaphore - BinarySemaphore management
bye - Exit console client
cd - ContainerDirectory management
cfgreg - Basis Configurator
checktopic - CheckTopic management
cnd - ContainerNameDirectory management
conditionalvariable - ConditionalVariable management
connection - Connection management
context - Execution context management (i.e., threads)
converter - Converter management
cpuresctrl - Manage cpu resources such as last-level cache allocation
crash - Crash management
crypto - Cryptography management (SSL/SAML/X509/Encryption).
csaccessor - Display diagnostics related to the CSAccessor library
ddlcontextstore - Get DdlContextStore information
deadlockdetector - Deadlock detector.
debug - Debug management
distribute - Handling distributed systems
dvol - DataVolume management
ELF - ELF symbol resolution management
encryption - Persistence encryption management
eslog - Manipulate logger on extended storage
event - Event management
exit - Exit console client
flightrecorder - Flight Recorder
hananet - HANA-Net command interface
help - Display help for a command or command list
hkt - HANA Kernal Tracer (HKT) management
indexmanager - Get IndexManager information, especially for IndexHandles
itab - Internaltable diagnostics
jexec - Information and actions for Job Executor/Scheduler
licensing - Licensing management.
log - Show information about logger and manipulate logger
machine - Information about the machine topology
mm - Memory management
monitor - Monitor view command
mproxy - Malloc proxy management
msl - Mid size LOB management
mutex - Mutex management
numa - Provides NUMA statistics for all columns of a given table, broken down by column constituents like dictionary, data vector and index.
nvmprovider - NVM Provider
output - Command for managing output from the hdbcons
page - Page management
pageaccess - PageAccess management
profiler - Profiler
quit - Exit console client
readwritelock - ReadWriteLock management
replication - Monitor data and log replication
resman - ResourceManager management
rowstore - Row Store
runtimedump - Generate a runtime dump.
savepoint - Savepoint management
semaphore - Semaphore management
servicethreads - Thread information M_SERVICE_THREADS
snapshot - Snapshot management
stat - Statistics management
statisticsservercontroller - StatisticsServer internals
statreg - Statistics registry command
syncprimi - Syncprimitive management (Mutex, CondVariable, Semaphore, BinarySemaphore,
ReadWriteLock)
table - Table Management
tablepreload - Manage and monitor table preload
trace - Trace management
tracetopic - TraceTopic management
transaction - Transaction management
ut - UnifiedTable Management
version - Version management
vf - VirtualFile management
x2 - get X2 info
[OK]
## Finish command at: 2023-06-22 09:07:16.785 command took: 209.000 usec
--
[EXIT]
--
[BYE]

If you want to use SAP HANA System Replication, a backup must first be created on the primary system.

Example of how to perform this is as user <sid>adm:

clusternode1:rh2adm> hdbsql -i ${TINSTANCE} -u system -d SYSTEMDB "BACKUP DATA USING FILE ('/hana/backup/')"
clusternode1:rh2adm> hdbsql -i ${TINSTANCE} -u system -d ${SAPSYSTEMNAME} "BACKUP DATA USING FILE ('/hana/backup/')"

SAP HANA System Replication has to be enabled on the primary node. This requires a backup to be done first.

clusternode1:rh2adm> hdbnsutil -sr_enable --name=DC1
nameserver is active, proceeding ...
successfully enabled system as system replication source site
done.

The database keys need to be copied from the primary to the secondary database before it can be registered as a secondary.

For example:

clusternode1:rh2adm> scp -rp /usr/sap/${SAPSYSTEMNAME}/SYS/global/security/rsecssfs/data/SSFS_${SAPSYSTEMNAME}.DAT  remotehost3:/usr/sap/${SAPSYSTEMNAME}/SYS/global/security/rsecssfs/data/SSFS_${SAPSYSTEMNAME}.DAT
clusternode1:rh2adm> scp -rp /usr/sap/${SAPSYSTEMNAME}/SYS/global/security/rsecssfs/key/SSFS_${SAPSYSTEMNAME}.KEY remotehost3:/usr/sap/${SAPSYSTEMNAME}/SYS/global/security/rsecssfs/key/SSFS_${SAPSYSTEMNAME}.KEY

Please ensure that the database keys have been copied to the secondary nodes first. Then run the registration command:

clusternode1:rh2adm> hdbnsutil -sr_register --remoteHost=remotehost3 --remoteInstance=${TINSTANCE} --replicationMode=syncmem --name=DC1 --remoteName=DC3 --operationMode=logreplay --online

Parameter description:

There are two options for setting the log_mode:

Example including a wrong overwrite entry:

clusternode1:rh2adm> hdbsql -i ${TINSTANCE} -d ${SAPSYSTEMNAME} -u system
Password:

Welcome to the SAP HANA Database interactive terminal.

Type:  \h for help with commands
       \q to quit

hdbsql RH2=> select * from m_inifile_contents where key='log_mode'
FILE_NAME,LAYER_NAME,TENANT_NAME,HOST,SECTION,KEY,VALUE
"global.ini","DEFAULT","","","persistence","log_mode","normal"
"global.ini","HOST","","node2","persistence","log_mode","overwrite"
2 rows selected (overall time 46.931 msec; server time 30.845 msec)

hdbsql RH2=>exit

In this case, we have two global.ini files:

Example:

clusternode1:rh2adm> vim /hana/shared/${SAPSYSTEMNAME}/HDB${TINSTANCE}/${HOSTNAME}/global.ini
# global.ini last modified 2023-04-06 16:15:03.521715 by hdbnameserver
[persistence]
log_mode = overwrite

# global.ini last modified 2023-04-06 16:15:03.521715 by hdbnameserver
[persistence]
log_mode = normal

After having checked or updated the global.ini file(s), verify the log_mode values:

clusternode1:rh2adm> hdbsql -d ${SAPSYSTEMNAME} -i ${TINSTANCE} -u SYSTEM;
hdbsql RH2=> select * from m_inifile_contents where section='persistence' and key='log_mode'
FILE_NAME,LAYER_NAME,TENANT_NAME,HOST,SECTION,KEY,VALUE
"global.ini","DEFAULT","","","persistence","log_mode","normal"
"global.ini","HOST","","node2","persistence","log_mode","normal"
2 rows selected (overall time 60.982 msec; server time 20.420 msec)

The section also shows that this parameter needs to be set in the [persistence] section. When you change the log mode from overwrite to normal, it is recommended that you create a full data backup to ensure that the database can be recovered.

There are several ways to identify the primary node, for instance:

Option 1 - The following example of the systemReplicationStatus.py script and filter will return the primary database location on all nodes:

clusternode1:rh2adm>
/usr/sap/${SAPSYSTEMNAME}/HDB${TINSTANCE}/exe/Python/bin/python
/usr/sap/${SAPSYSTEMNAME}/HDB${TINSTANCE}/exe/python_support/systemReplicationStatus.py --sapcontrol=1 | egrep -e
"3${TINSTANCE}01/HOST|PRIMARY_MASTERS"| head -1 | awk -F"=" '{ print $2 }'

Output:

clusternode2

Option 2 - The following example displays the systemReplicationStatus in a similar way for all nodes:

rh2adm>hdbnsutil -sr_state --sapcontrol=1 | grep site.*Mode

Output:

siteReplicationMode/DC1=primary
siteReplicationMode/DC3=async
siteReplicationMode/DC2=syncmem
siteOperationMode/DC1=primary
siteOperationMode/DC3=logreplay
siteOperationMode/DC2=logreplay

Please refer to Check the Replication status section for check on the primary and the secondary nodes. Also:

Example for enabling maintenance-mode for the cluster:

[root@clusternode1]# pcs property set maintenance-mode=true

On the secondary that is to become the new primary, run as <sidadm> user:

clusternode1:rh2adm> hdbnsutil -sr_takeover

This secondary becomes the primary, other active secondary databases get re-registered to the new primary and the old primary needs to be manually re-registered as secondary.

Please ensure that the cluster is stopped or put in maintenance-mode. Example:

clusternode2:rh2adm> hdbnsutil -sr_register --remoteHost=remotehost3 --remoteInstance=${TINSTANCE} --replicationMode=syncmem --name=DC2 --online --remoteName=DC3 --operationMode=logreplay --force_full_replica --online

In our examples, we are using full replication. Your SAP HANA system administrator should know when full replication is required.

Please refer to Check the SAP HANA System Replication status and Discover the primary node. It is important that the information is consistent. If a node is not part of the systemReplicationStatus.py output and has a different system replication state, please check with your database administrator if this node needs to be re-registered.

One way of solving this is to re-register this site as a new secondary.

Sometimes a secondary instance will still not come up. Then unregister this site before you re-register it again. Example of unregistering the secondary DC1:

clusternode1:rh2adm> hdbnsutil -sr_unregister --name=DC1

Example of re-registering DC1:

clusternode1:rh2adm> hdbnsutil -sr_register --name=DC1 --remoteHost=node2 --remoteInstance=02 --replicationMode=sync --operationMode=logreplay --online

The database needs to be started and checked if it is running. Finally check the replication status.

To start the cluster on all nodes execute the following command:

# pcs cluster start -all

After a reboot, the cluster will be started automatically only if the service is enabled. The command will help to know if the cluster has started and if the daemons are enabled to be autostarted.

# pcs cluster status

The cluster auto-start can be enabled with:

# pcs cluster enable --all

Other options are:

For more details, please check the pcs cluster help:

# pcs cluster stop --all
# pcs cluster help

If you want to make changes and you want to avoid interference bythe pacemaker cluster, you can "freeze" the cluster by putting it into maintenance-mode:

# pcs property set maintenance-mode=true

An easy way to verify maintenance-mode is to check if the resources are unmanaged:

# pcs resource
  * Clone Set: SAPHanaTopology_RH2_02-clone [SAPHanaTopology_RH2_02] (unmanaged):
    * SAPHanaTopology_RH2_02    (ocf:heartbeat:SAPHanaTopology):         Started clusternode1 (unmanaged)
    * SAPHanaTopology_RH2_02    (ocf:heartbeat:SAPHanaTopology):         Started clusternode2 (unmanaged)
  * Clone Set: SAPHana_RH2_02-clone [SAPHana_RH2_02] (promotable, unmanaged):
    * SAPHana_RH2_02    (ocf:heartbeat:SAPHana):         Unpromoted clusternode1 (unmanaged)
    * SAPHana_RH2_02    (ocf:heartbeat:SAPHana):         Promoted clusternode2 (unmanaged)
  * vip_RH2_02_MASTER   (ocf:heartbeat:IPaddr2):         Started clusternode2 (unmanaged)

Refresh cluster resources to detect the resource state while the cluster is in maintenance-mode and does not update resource status changes:

# pcs resource refresh

This will indicate if anything is not yet correct and will cause remediation action by the cluster, as soon as it is taken out of maintenance-mode.

Remove the maintenance-mode by running:

# pcs property set maintenance-mode=false

Now the cluster will continue to work. If something is configured wrong, it will react now.

Following are several ways to check the cluster status:

Example:

# pcs status --full
Cluster name: cluster1
Status of pacemakerd: 'Pacemaker is running' (last updated 2023-06-22 17:56:01 +02:00)
Cluster Summary:
  * Stack: corosync
  * Current DC: clusternode2 (2) (version 2.1.5-7.el9-a3f44794f94) - partition with quorum
  * Last updated: Thu Jun 22 17:56:01 2023
  * Last change:  Thu Jun 22 17:53:34 2023 by root via crm_attribute on clusternode1
  * 2 nodes configured
  * 6 resource instances configured
Node List:
  * Node clusternode1 (1): online, feature set 3.16.2
  * Node clusternode2 (2): online, feature set 3.16.2
Full List of Resources:
  * h7fence	(stonith:fence_rhevm):	 Started clusternode2
  * Clone Set: SAPHanaTopology_RH2_02-clone [SAPHanaTopology_RH2_02]:
    * SAPHanaTopology_RH2_02	(ocf:heartbeat:SAPHanaTopology):	 Started clusternode1
    * SAPHanaTopology_RH2_02	(ocf:heartbeat:SAPHanaTopology):	 Started clusternode2
  * Clone Set: SAPHana_RH2_02-clone [SAPHana_RH2_02] (promotable):
    * SAPHana_RH2_02	(ocf:heartbeat:SAPHana):	 Promoted clusternode1
    * SAPHana_RH2_02	(ocf:heartbeat:SAPHana):	 Unpromoted clusternode2
  * vip_RH2_02_MASTER	(ocf:heartbeat:IPaddr2):	 Started clusternode1
Node Attributes:
  * Node: clusternode1 (1):
    * hana_rh2_clone_state            	: PROMOTED
    * hana_rh2_op_mode                	: logreplay
    * hana_rh2_remoteHost             	: clusternode2
    * hana_rh2_roles                  	: 4:P:master1:master:worker:master
    * hana_rh2_site                   	: DC1
    * hana_rh2_sra                    	: -
    * hana_rh2_srah                   	: -
    * hana_rh2_srmode                 	: syncmem
    * hana_rh2_sync_state             	: PRIM
    * hana_rh2_version                	: 2.00.059.02
    * hana_rh2_vhost                  	: clusternode1
    * lpa_rh2_lpt                     	: 1687449214
    * master-SAPHana_RH2_02           	: 150
  * Node: clusternode2 (2):
    * hana_rh2_clone_state            	: DEMOTED
    * hana_rh2_op_mode                	: logreplay
    * hana_rh2_remoteHost             	: clusternode1
    * hana_rh2_roles                  	: 4:S:master1:master:worker:master
    * hana_rh2_site                   	: DC2
    * hana_rh2_sra                    	: -
    * hana_rh2_srah                   	: -
    * hana_rh2_srmode                 	: syncmem
    * hana_rh2_sync_state             	: SOK
    * hana_rh2_version                	: 2.00.059.02
    * hana_rh2_vhost                  	: clusternode2
    * lpa_rh2_lpt                     	: 30
    * master-SAPHana_RH2_02           	: 100
Migration Summary:
Tickets:
PCSD Status:
  clusternode1: Online
  clusternode2: Online
Daemon Status:
  corosync: active/enabled
  pacemaker: active/enabled
  pcsd: active/enabled

Use pcs resource to check the status of all resources. This prints the list and the current status of the resources.

Example:

# pcs resource
  * Clone Set: SAPHanaTopology_RH2_02-clone [SAPHanaTopology_RH2_02]:
    * Started: [ clusternode1 clusternode2 ]
  * Clone Set: SAPHana_RH2_02-clone [SAPHana_RH2_02] (promotable):
    * Promoted: [ clusternode1 ]
    * Unpromoted: [ clusternode2 ]
  * vip_RH2_02_MASTER	(ocf:heartbeat:IPaddr2):	 Started clusternode1

The following displays the current resource configuration:

# pcs resource config
Resource: vip_RH2_02_MASTER (class=ocf provider=heartbeat type=IPaddr2)
  Attributes: vip_RH2_02_MASTER-instance_attributes
    ip=192.168.5.136
  Operations:
    monitor: vip_RH2_02_MASTER-monitor-interval-10s
      interval=10s
      timeout=20s
    start: vip_RH2_02_MASTER-start-interval-0s
      interval=0s
      timeout=20s
    stop: vip_RH2_02_MASTER-stop-interval-0s
      interval=0s
      timeout=20s
Clone: SAPHanaTopology_RH2_02-clone
  Meta Attributes: SAPHanaTopology_RH2_02-clone-meta_attributes
    clone-max=2
    clone-node-max=1
    interleave=true
  Resource: SAPHanaTopology_RH2_02 (class=ocf provider=heartbeat type=SAPHanaTopology)
    Attributes: SAPHanaTopology_RH2_02-instance_attributes
      InstanceNumber=02
      SID=RH2
    Operations:
      methods: SAPHanaTopology_RH2_02-methods-interval-0s
        interval=0s
        timeout=5
      monitor: SAPHanaTopology_RH2_02-monitor-interval-10
        interval=10
        timeout=600
      reload: SAPHanaTopology_RH2_02-reload-interval-0s
        interval=0s
        timeout=5
      start: SAPHanaTopology_RH2_02-start-interval-0s
        interval=0s
        timeout=600
      stop: SAPHanaTopology_RH2_02-stop-interval-0s
        interval=0s
        timeout=600
Clone: SAPHana_RH2_02-clone
  Meta Attributes: SAPHana_RH2_02-clone-meta_attributes
    clone-max=2
    clone-node-max=1
    interleave=true
    notify=true
    promotable=true
  Resource: SAPHana_RH2_02 (class=ocf provider=heartbeat type=SAPHana)
    Attributes: SAPHana_RH2_02-instance_attributes
      AUTOMATED_REGISTER=true
      DUPLICATE_PRIMARY_TIMEOUT=300
      HANA_CALL_TIMEOUT=10
      InstanceNumber=02
      PREFER_SITE_TAKEOVER=true
      SID=RH2
    Operations:
      demote: SAPHana_RH2_02-demote-interval-0s
        interval=0s
        timeout=3600
      methods: SAPHana_RH2_02-methods-interval-0s
        interval=0s
        timeout=5
      monitor: SAPHana_RH2_02-monitor-interval-251
        interval=251
        timeout=700
        role=Unpromoted
      monitor: SAPHana_RH2_02-monitor-interval-249
        interval=249
        timeout=700
        role=Promoted
      promote: SAPHana_RH2_02-promote-interval-0s
        interval=0s
        timeout=3600
      reload: SAPHana_RH2_02-reload-interval-0s
        interval=0s
        timeout=5
      start: SAPHana_RH2_02-start-interval-0s
        interval=0s
        timeout=3200
      stop: SAPHana_RH2_02-stop-interval-0s
        interval=0s
        timeout=3100

This lists all the parameters which are used to configure the installed and configured resource agent.

If this option is used in the SAPHana resource, pacemaker will automatically re-register the secondary database.

It is recommended to use this option for the first tests. When using AUTOMATED_REGISTER=false the administrator needs to re-register the secondary node manually.

There are several options for managing resources. For more information, please check out the help available:

# pcs resource help

List the used resource agents:

# pcs resource config | grep "type=" | awk -F"type=" '{ print $2 }' | sed -e "s/)//g"

Example output:

IPaddr2
SAPHanaTopology
SAPHana

Display specific resource agent description and configuration parameters:

# pcs resource describe <resource agent>

Example (without output):

# pcs resource describe IPaddr2

Example of resource agent IPaddr2 (with output):

Assumed agent name 'ocf:heartbeat:IPaddr2' (deduced from 'IPaddr2')
ocf:heartbeat:IPaddr2 - Manages virtual IPv4 and IPv6 addresses (Linux specific version)

This Linux-specific resource manages IP alias IP addresses. It can add an IP alias, or remove one. In
addition, it can implement Cluster Alias IP functionality if invoked as a clone resource.  If used as a
clone, "shared address with a trivial, stateless (autonomous) load-balancing/mutual exclusion on
ingress" mode gets applied (as opposed to "assume resource uniqueness" mode otherwise). For that, Linux
firewall (kernel and userspace) is assumed, and since recent distributions are ambivalent in plain
"iptables" command to particular back-end resolution, "iptables-legacy" (when present) gets prioritized
so as to avoid incompatibilities (note that respective ipt_CLUSTERIP firewall extension in use here is,
at the same time, marked deprecated, yet said "legacy" layer can make it workable, literally, to this
day) with "netfilter" one (as in "iptables-nft"). In that case, you should explicitly set clone-node-max
>= 2, and/or clone-max < number of nodes. In case of node failure, clone instances need to be re-
allocated on surviving nodes. This would not be possible if there is already an instance on those nodes,
and clone-node-max=1 (which is the default).  When the specified IP address gets assigned to a
respective interface, the resource agent sends unsolicited ARP (Address Resolution Protocol, IPv4) or NA
(Neighbor Advertisement, IPv6) packets to inform neighboring machines about the change. This
functionality is controlled for both IPv4 and IPv6 by shared 'arp_*' parameters.

Resource options:
  ip (required) (unique): The IPv4 (dotted quad notation) or IPv6 address (colon hexadecimal notation)
      example IPv4 "192.168.1.1". example IPv6 "2001:db8:DC28:0:0:FC57:D4C8:1FFF".
  nic: The base network interface on which the IP address will be brought online.  If left empty, the
      script will try and determine this from the routing table.  Do NOT specify an alias interface in
      the form eth0:1 or anything here; rather, specify the base interface only. If you want a label,
      see the iflabel parameter.  Prerequisite:  There must be at least one static IP address, which is
      not managed by the cluster, assigned to the network interface. If you can not assign any static IP
      address on the interface, modify this kernel parameter:  sysctl -w
      net.ipv4.conf.all.promote_secondaries=1 # (or per device)
  cidr_netmask: The netmask for the interface in CIDR format (e.g., 24 and not 255.255.255.0)  If
      unspecified, the script will also try to determine this from the routing table.
  broadcast: Broadcast address associated with the IP. It is possible to use the special symbols '+' and
      '-' instead of the broadcast address. In this case, the broadcast address is derived by
      setting/resetting the host bits of the interface prefix.
  iflabel: You can specify an additional label for your IP address here. This label is appended to your
      interface name.  The kernel allows alphanumeric labels up to a maximum length of 15 characters
      including the interface name and colon (e.g. eth0:foobar1234)  A label can be specified in nic
      parameter but it is deprecated. If a label is specified in nic name, this parameter has no effect.
  lvs_support: Enable support for LVS Direct Routing configurations. In case a IP address is stopped,
      only move it to the loopback device to allow the local node to continue to service requests, but
      no longer advertise it on the network.  Notes for IPv6: It is not necessary to enable this option
      on IPv6. Instead, enable 'lvs_ipv6_addrlabel' option for LVS-DR usage on IPv6.
  lvs_ipv6_addrlabel: Enable adding IPv6 address label so IPv6 traffic originating from the address's
      interface does not use this address as the source. This is necessary for LVS-DR health checks to
      realservers to work. Without it, the most recently added IPv6 address (probably the address added
      by IPaddr2) will be used as the source address for IPv6 traffic from that interface and since that
      address exists on loopback on the realservers, the realserver response to pings/connections will
      never leave its loopback. See RFC3484 for the detail of the source address selection.  See also
      'lvs_ipv6_addrlabel_value' parameter.
  lvs_ipv6_addrlabel_value: Specify IPv6 address label value used when 'lvs_ipv6_addrlabel' is enabled.
      The value should be an unused label in the policy table which is shown by 'ip addrlabel list'
      command. You would rarely need to change this parameter.
  mac: Set the interface MAC address explicitly. Currently only used in case of the Cluster IP Alias.
      Leave empty to chose automatically.
  clusterip_hash: Specify the hashing algorithm used for the Cluster IP functionality.
  unique_clone_address: If true, add the clone ID to the supplied value of IP to create a unique address
      to manage
  arp_interval: Specify the interval between unsolicited ARP (IPv4) or NA (IPv6) packets in
      milliseconds.  This parameter is deprecated and used for the backward compatibility only. It is
      effective only for the send_arp binary which is built with libnet, and send_ua for IPv6. It has no
      effect for other arp_sender.
  arp_count: Number of unsolicited ARP (IPv4) or NA (IPv6) packets to send at resource initialization.
  arp_count_refresh: For IPv4, number of unsolicited ARP packets to send during resource monitoring.
      Doing so helps mitigate issues of stuck ARP caches resulting from split-brain situations.
  arp_bg: Whether or not to send the ARP (IPv4) or NA (IPv6) packets in the background. The default is
      true for IPv4 and false for IPv6.
  arp_sender: For IPv4, the program to send ARP packets with on start. Available options are:  -
      send_arp: default  - ipoibarping: default for infiniband interfaces if ipoibarping is available  -
      iputils_arping: use arping in iputils package  - libnet_arping: use another variant of arping
      based on libnet
  send_arp_opts: For IPv4, extra options to pass to the arp_sender program. Available options are vary
      depending on which arp_sender is used.  A typical use case is specifying '-A' for iputils_arping
      to use ARP REPLY instead of ARP REQUEST as Gratuitous ARPs.
  flush_routes: Flush the routing table on stop. This is for applications which use the cluster IP
      address and which run on the same physical host that the IP address lives on. The Linux kernel may
      force that application to take a shortcut to the local loopback interface, instead of the
      interface the address is really bound to. Under those circumstances, an application may, somewhat
      unexpectedly, continue to use connections for some time even after the IP address is deconfigured.
      Set this parameter in order to immediately disable said shortcut when the IP address goes away.
  run_arping: For IPv4, whether or not to run arping for collision detection check.
  nodad: For IPv6, do not perform Duplicate Address Detection when adding the address.
  noprefixroute: Use noprefixroute flag (see 'man ip-address').
  preferred_lft: For IPv6, set the preferred lifetime of the IP address. This can be used to ensure that
      the created IP address will not be used as a source address for routing. Expects a value as
      specified in section 5.5.4 of RFC 4862.
  network_namespace: Specifies the network namespace to operate within. The namespace must already
      exist, and the interface to be used must be within the namespace.

Default operations:
  start:
    interval=0s
    timeout=20s
  stop:
    interval=0s
    timeout=20s
  monitor:
    interval=10s
    timeout=20s

If the cluster is stopped, all the resources will be stopped as well; if the cluster is put into maintenance-mode, all resources remain in their current status but will not be monitored or managed.

List all defined properties:

[root@clusternode1] pcs property
Cluster Properties:
 cluster-infrastructure: corosync
 cluster-name: cluster1
 concurrent-fencing: true
 dc-version: 2.1.5-7.el9-a3f44794f94
 hana_rh2_site_srHook_DC1: PRIM
 hana_rh2_site_srHook_DC2: SFAIL
 have-watchdog: false
 last-lrm-refresh: 1688548036
 maintenance-mode: true
 priority-fencing-delay: 10s
 stonith-enabled: true
 stonith-timeout: 900

To reconfigure the database, the cluster must be instructed to ignore any changes until the configuration is complete. You can put the cluster into maintenance-mode using:

# pcs property set maintenance-mode=true

Check the maintenance-mode:

# pcs resource
  * Clone Set: SAPHanaTopology_RH2_02-clone [SAPHanaTopology_RH2_02] (unmanaged):
    * SAPHanaTopology_RH2_02	(ocf:heartbeat:SAPHanaTopology):	 Started clusternode1 (unmanaged)
    * SAPHanaTopology_RH2_02	(ocf:heartbeat:SAPHanaTopology):	 Started clusternode2 (unmanaged)
  * Clone Set: SAPHana_RH2_02-clone [SAPHana_RH2_02] (promotable, unmanaged):
    * SAPHana_RH2_02	(ocf:heartbeat:SAPHana):	 Promoted clusternode1 (unmanaged)
    * SAPHana_RH2_02	(ocf:heartbeat:SAPHana):	 Unpromoted clusternode2 (unmanaged)
  * vip_RH2_02_MASTER	(ocf:heartbeat:IPaddr2):	 Started clusternode1 (unmanaged)

Verify that all resources are "unmanaged":

[root@clusternode1]# pcs status
Cluster name: cluster1
Status of pacemakerd: 'Pacemaker is running' (last updated 2023-06-27 16:02:15 +02:00)
Cluster Summary:
  * Stack: corosync
  * Current DC: clusternode2 (version 2.1.5-7.el9-a3f44794f94) - partition with quorum
  * Last updated: Tue Jun 27 16:02:16 2023
  * Last change:  Tue Jun 27 16:02:14 2023 by root via cibadmin on clusternode1
  * 2 nodes configured
  * 6 resource instances configured

              *** Resource management is DISABLED ***
  The cluster will not attempt to start, stop or recover services

Node List:
  * Online: [ clusternode1 clusternode2 ]

Full List of Resources:
  * h7fence	(stonith:fence_rhevm):	 Started clusternode2 (unmanaged)
  * Clone Set: SAPHanaTopology_RH2_02-clone [SAPHanaTopology_RH2_02] (unmanaged):
    * SAPHanaTopology_RH2_02	(ocf:heartbeat:SAPHanaTopology):	 Started clusternode1 (unmanaged)
    * SAPHanaTopology_RH2_02	(ocf:heartbeat:SAPHanaTopology):	 Started clusternode2 (unmanaged)
  * Clone Set: SAPHana_RH2_02-clone [SAPHana_RH2_02] (promotable, unmanaged):
    * SAPHana_RH2_02	(ocf:heartbeat:SAPHana):	 Promoted clusternode1 (unmanaged)
    * SAPHana_RH2_02	(ocf:heartbeat:SAPHana):	 Unpromoted clusternode2 (unmanaged)
  * vip_RH2_02_MASTER	(ocf:heartbeat:IPaddr2):	 Started clusternode1 (unmanaged)

Daemon Status:
  corosync: active/enabled
  pacemaker: active/enabled
  pcsd: active/enabled

The resources will switch back to managed if you unset the maintenance-mode:

# pcs property set maintenance-mode=false

A simple example of how to failover the SAP HANA database is to use the pcs resource move command. You need to use the clone resource name and move the resource as shown below:

# pcs resource move <SAPHana-clone-resource>

In this example, the clone resource is SAPHana_RH2_02-clone:

[root@clusternode1]# pcs resource
  * Clone Set: SAPHanaTopology_RH2_02-clone [SAPHanaTopology_RH2_02]:
    * Started: [ clusternode1 clusternode2 ]
  * Clone Set: SAPHana_RH2_02-clone [SAPHana_RH2_02] (promotable):
    * Promoted: [ clusternode1 ]
    * Unpromoted: [ clusternode2 ]
  * vip_RH2_02_MASTER	(ocf:heartbeat:IPaddr2):	 Started clusternode1

Move the resource:

# pcs resource move SAPHana_RH2_02-clone
Location constraint to move resource 'SAPHana_RH2_02-clone' has been created
Waiting for the cluster to apply configuration changes...
Location constraint created to move resource 'SAPHana_RH2_02-clone' has been removed
Waiting for the cluster to apply configuration changes...
resource 'SAPHana_RH2_02-clone' is promoted on node 'clusternode2'; unpromoted on node 'clusternode1'

Check if there are remaining constraints:

# pcs constraint location

You can remove those location constraints created during the failover by clearing the resource. Example:

[root@clusternode1]# pcs resource clear SAPHana_RH2_02-clone

Check if there are any remaining warnings or entries in the "Migration Summary":

# pcs status --full

Check the stonith history:

# pcs stonith history

If desired, clear the stonith history:

# pcs stonith history cleanup

If you are using a pacemaker version earlier than 2.1.5, please refer to Is there a way to manage constraints when running pcs resource move? and check the remaining constraints.

All pacemaker activities are logged in the /var/log/messages file on the cluster nodes. Since there are many other messages, it is sometimes difficult to read the messages related to the SAP resource agent. You can configure a command alias that filters out only the messages related to SAP resource agent.

Example alias tmsl:

# alias tmsl='tail -1000f /var/log/messages | egrep -s "Setting master-rsc_SAPHana_${SAPSYSTEMNAME}_HDB${TINSTANCE}|sr_register|WAITING4LPA|PROMOTED|DEMOTED|UNDEFINED|master_walk|SWAIT|WaitforStopped|FAILED|LPT"'

Example output of tsml:

[root@clusternode1]# tmsl
Jun 22 13:59:54 clusternode1 SAPHana(SAPHana_RH2_02)[907482]: INFO: DEC: Finally get_SRHOOK()=SOK
Jun 22 13:59:55 clusternode1 SAPHana(SAPHana_RH2_02)[907482]: INFO: DEC: secondary with sync status SOK ==> possible takeover node
Jun 22 13:59:55 clusternode1 SAPHana(SAPHana_RH2_02)[907482]: INFO: DEC: hana_rh2_site_srHook_DC1=SWAIT
Jun 22 13:59:55 clusternode1 SAPHana(SAPHana_RH2_02)[907482]: INFO: DEC: hana_rh2_site_srHook_DC1 is empty or SWAIT. Take polling attribute: hana_rh2_sync_state=SOK
Jun 22 13:59:55 clusternode1 SAPHana(SAPHana_RH2_02)[907482]: INFO: DEC: Finally get_SRHOOK()=SOK
Jun 22 13:59:55 clusternode1 SAPHana(SAPHana_RH2_02)[907482]: INFO: DEC: saphana_monitor_secondary: scoring_crm_master(4:S:master1:master:worker:master,SOK)
Jun 22 13:59:55 clusternode1 SAPHana(SAPHana_RH2_02)[907482]: INFO: DEC: scoring_crm_master: sync(SOK) is matching syncPattern (SOK)
Jun 22 14:04:06 clusternode1 SAPHana(SAPHana_RH2_02)[914625]: INFO: DEC: hana_rh2_site_srHook_DC1=SWAIT
Jun 22 14:04:06 clusternode1 SAPHana(SAPHana_RH2_02)[914625]: INFO: DEC: hana_rh2_site_srHook_DC1 is empty or SWAIT. Take polling attribute: hana_rh2_sync_state=SOK
Jun 22 14:04:06 clusternode1 SAPHana(SAPHana_RH2_02)[914625]: INFO: DEC: Finally get_SRHOOK()=SOK
Jun 22 14:04:09 clusternode1 SAPHana(SAPHana_RH2_02)[914625]: INFO: DEC: hana_rh2_site_srHook_DC1=SWAIT
Jun 22 14:04:09 clusternode1 SAPHana(SAPHana_RH2_02)[914625]: INFO: DEC: hana_rh2_site_srHook_DC1 is empty or SWAIT. Take polling attribute: hana_rh2_sync_state=SOK
Jun 22 14:04:09 clusternode1 SAPHana(SAPHana_RH2_02)[914625]: INFO: DEC: Finally get_SRHOOK()=SOK
Jun 22 14:04:09 clusternode1 SAPHana(SAPHana_RH2_02)[914625]: INFO: DEC: secondary with sync status SOK ==> possible takeover node
Jun 22 14:04:09 clusternode1 SAPHana(SAPHana_RH2_02)[914625]: INFO: DEC: hana_rh2_site_srHook_DC1=SWAIT
Jun 22 14:04:09 clusternode1 SAPHana(SAPHana_RH2_02)[914625]: INFO: DEC: hana_rh2_site_srHook_DC1 is empty or SWAIT. Take polling attribute: hana_rh2_sync_state=SOK
Jun 22 14:04:09 clusternode1 SAPHana(SAPHana_RH2_02)[914625]: INFO: DEC: Finally get_SRHOOK()=SOK
Jun 22 14:04:09 clusternode1 SAPHana(SAPHana_RH2_02)[914625]: INFO: DEC: saphana_monitor_secondary: scoring_crm_master(4:S:master1:master:worker:master,SOK)
Jun 22 14:04:09 clusternode1 SAPHana(SAPHana_RH2_02)[914625]: INFO: DEC: scoring_crm_master: sync(SOK) is matching syncPattern (SOK)
Jun 22 14:08:21 clusternode1 SAPHana(SAPHana_RH2_02)[922136]: INFO: DEC: hana_rh2_site_srHook_DC1=SWAIT
Jun 22 14:08:21 clusternode1 SAPHana(SAPHana_RH2_02)[922136]: INFO: DEC: hana_rh2_site_srHook_DC1 is empty or SWAIT. Take polling attribute: hana_rh2_sync_state=SOK
Jun 22 14:08:21 clusternode1 SAPHana(SAPHana_RH2_02)[922136]: INFO: DEC: Finally get_SRHOOK()=SOK
Jun 22 14:08:23 clusternode1 SAPHana(SAPHana_RH2_02)[922136]: INFO: DEC: hana_rh2_site_srHook_DC1=SWAIT
Jun 22 14:08:23 clusternode1 SAPHana(SAPHana_RH2_02)[922136]: INFO: DEC: hana_rh2_site_srHook_DC1 is empty or SWAIT. Take polling attribute: hana_rh2_sync_state=SOK
Jun 22 14:08:23 clusternode1 SAPHana(SAPHana_RH2_02)[922136]: INFO: DEC: Finally get_SRHOOK()=SOK
Jun 22 14:08:24 clusternode1 SAPHana(SAPHana_RH2_02)[922136]: INFO: DEC: secondary with sync status SOK ==> possible takeover node
Jun 22 14:08:24 clusternode1 SAPHana(SAPHana_RH2_02)[922136]: INFO: DEC: hana_rh2_site_srHook_DC1=SWAIT
Jun 22 14:08:24 clusternode1 SAPHana(SAPHana_RH2_02)[922136]: INFO: DEC: hana_rh2_site_srHook_DC1 is empty or SWAIT. Take polling attribute: hana_rh2_sync_state=SOK
Jun 22 14:08:24 clusternode1 SAPHana(SAPHana_RH2_02)[922136]: INFO: DEC: Finally get_SRHOOK()=SOK
Jun 22 14:08:24 clusternode1 SAPHana(SAPHana_RH2_02)[922136]: INFO: DEC: saphana_monitor_secondary: scoring_crm_master(4:S:master1:master:worker:master,SOK)
Jun 22 14:08:24 clusternode1 SAPHana(SAPHana_RH2_02)[922136]: INFO: DEC: scoring_crm_master: sync(SOK) is matching syncPattern (SOK)
Jun 22 14:12:35 clusternode1 SAPHana(SAPHana_RH2_02)[929408]: INFO: DEC: hana_rh2_site_srHook_DC1=SWAIT
Jun 22 14:12:35 clusternode1 SAPHana(SAPHana_RH2_02)[929408]: INFO: DEC: hana_rh2_site_srHook_DC1 is empty or SWAIT. Take polling attribute: hana_rh2_sync_state=SOK
Jun 22 14:12:36 clusternode1 SAPHana(SAPHana_RH2_02)[929408]: INFO: DEC: Finally get_SRHOOK()=SOK
Jun 22 14:12:38 clusternode1 SAPHana(SAPHana_RH2_02)[929408]: INFO: DEC: hana_rh2_site_srHook_DC1=SWAIT
Jun 22 14:12:38 clusternode1 SAPHana(SAPHana_RH2_02)[929408]: INFO: DEC: hana_rh2_site_srHook_DC1 is empty or SWAIT. Take polling attribute: hana_rh2_sync_state=SOK
Jun 22 14:12:38 clusternode1 SAPHana(SAPHana_RH2_02)[929408]: INFO: DEC: Finally get_SRHOOK()=SOK
Jun 22 14:12:38 clusternode1 SAPHana(SAPHana_RH2_02)[929408]: INFO: DEC: secondary with sync status SOK ==> possible takeover node
Jun 22 14:12:39 clusternode1 SAPHana(SAPHana_RH2_02)[929408]: INFO: DEC: hana_rh2_site_srHook_DC1=SWAIT
Jun 22 14:12:39 clusternode1 SAPHana(SAPHana_RH2_02)[929408]: INFO: DEC: hana_rh2_site_srHook_DC1 is empty or SWAIT. Take polling attribute: hana_rh2_sync_state=SOK
Jun 22 14:12:39 clusternode1 SAPHana(SAPHana_RH2_02)[929408]: INFO: DEC: Finally get_SRHOOK()=SOK
Jun 22 14:12:39 clusternode1 SAPHana(SAPHana_RH2_02)[929408]: INFO: DEC: saphana_monitor_secondary: scoring_crm_master(4:S:master1:master:worker:master,SOK)
Jun 22 14:12:39 clusternode1 SAPHana(SAPHana_RH2_02)[929408]: INFO: DEC: scoring_crm_master: sync(SOK) is matching syncPattern (SOK)
Jun 22 14:14:01 clusternode1 pacemaker-attrd[10150]: notice: Setting hana_rh2_clone_state[clusternode2]: PROMOTED -> DEMOTED
Jun 22 14:14:02 clusternode1 pacemaker-attrd[10150]: notice: Setting hana_rh2_clone_state[clusternode2]: DEMOTED -> UNDEFINED
Jun 22 14:14:19 clusternode1 pacemaker-attrd[10150]: notice: Setting hana_rh2_clone_state[clusternode1]: DEMOTED -> PROMOTED
Jun 22 14:14:21 clusternode1 SAPHana(SAPHana_RH2_02)[932762]: INFO: DEC: hana_rh2_site_srHook_DC1=SWAIT
Jun 22 14:14:21 clusternode1 SAPHana(SAPHana_RH2_02)[932762]: INFO: DEC: hana_rh2_site_srHook_DC1 is empty or SWAIT. Take polling attribute: hana_rh2_sync_state=SOK
Jun 22 14:14:21 clusternode1 SAPHana(SAPHana_RH2_02)[932762]: INFO: DEC: Finally get_SRHOOK()=SOK
Jun 22 14:15:14 clusternode1 SAPHana(SAPHana_RH2_02)[932762]: INFO: DEC: hana_rh2_site_srHook_DC1=SWAIT
Jun 22 14:15:22 clusternode1 pacemaker-attrd[10150]: notice: Setting hana_rh2_sync_state[clusternode1]: SOK -> PRIM
Jun 22 14:15:23 clusternode1 pacemaker-attrd[10150]: notice: Setting hana_rh2_sync_state[clusternode2]: PRIM -> SOK
Jun 22 14:15:23 clusternode1 SAPHana(SAPHana_RH2_02)[934810]: INFO: ACT site=DC1, setting SOK for secondary (1)
Jun 22 14:15:25 clusternode1 pacemaker-attrd[10150]: notice: Setting hana_rh2_clone_state[clusternode2]: UNDEFINED -> DEMOTED
Jun 22 14:15:32 clusternode1 pacemaker-attrd[10150]: notice: Setting hana_rh2_sync_state[clusternode2]: SOK -> SFAIL
Jun 22 14:19:36 clusternode1 pacemaker-attrd[10150]: notice: Setting hana_rh2_sync_state[clusternode2]: SFAIL -> SOK
Jun 22 14:19:36 clusternode1 SAPHana(SAPHana_RH2_02)[942693]: INFO: ACT site=DC1, setting SOK for secondary (1)
Jun 22 14:23:49 clusternode1 SAPHana(SAPHana_RH2_02)[950623]: INFO: ACT site=DC1, setting SOK for secondary (1)
Jun 22 14:28:02 clusternode1 SAPHana(SAPHana_RH2_02)[958633]: INFO: ACT site=DC1, setting SOK for secondary (1)
Jun 22 14:32:15 clusternode1 SAPHana(SAPHana_RH2_02)[966683]: INFO: ACT site=DC1, setting SOK for secondary (1)
Jun 22 14:36:27 clusternode1 SAPHana(SAPHana_RH2_02)[974736]: INFO: ACT site=DC1, setting SOK for secondary (1)
Jun 22 14:40:40 clusternode1 SAPHana(SAPHana_RH2_02)[982934]: INFO: ACT site=DC1, setting SOK for secondary (1)

The filter makes it easier to understand what status changes are happening. If details are missing, you can open the whole message file to read all the information.

After a failover, you can clear the resource. Please also check that there are no remaining location constraints.

During the installation the resources are sometimes started before the configuration is finally completed. This can lead to entries in the Cluster Information Base (CIB), which can result in incorrect behavior. This can easily be checked and also manually corrected after the configuration has been completed.

If you start the SAPHana resources the missing entries will be recreated. Wrong entries cannot be addressed by pcs commands and need to be removed manually.

Check CIB entries:

# cibadmin --query

DC3 and SFAIL are entries that should not be present in the Cluster Information Base, when the cluster members are DC1 and DC2, and when the sync state between the nodes is reported as SOK.

Example to check for corresponding entries:

# cibadmin --query |grep '"DC3"'
# cibadmin --query |grep '"SFAIL"'

The command can be executed on any node in the cluster as user root. Usually the output of the command is empty. If there is still an error in the configuration the output could look like this:

        <nvpair id="SAPHanaSR-hana_rh1_glob_sec" name="hana_rh1_glob_sec" value="DC3"/>

These entries can be removed with the following command:

# cibadmin --delete --xml-text '<...>'

To remove the entries in the example above you have to enter the following. Please note that the output contains double quotes, so the text must be embedded in single quotes:

# cibadmin --delete --xml-text '        <nvpair id="SAPHanaSR-hana_rh1_glob_sec" name="hana_rh1_glob_sec" value="DC3"/>'

Verify the absence of the removed CIB entries. The returned output should be empty.

# cibadmin --query |grep 'DC3"'

During the failover tests there might be left behind constraints and other remains from previous tests. The cluster needs to be cleared from these before starting the next test.

Check the cluster status for failure events:

# pcs status --full

If you see cluster warnings or entries in the "Migration Summary", you should clear and cleanup the resources:

# pcs resource clear SAPHana_RH2_02-clone
# pcs resource cleanup SAPHana_RH2_02-clone

Output:

Cleaned up SAPHana_RH2_02:0 on clusternode1
Cleaned up SAPHana_RH2_02:1 on clusternode2

Check if there are unwanted location constraints, for example from a previous failover:

# pcs constraint location

Check the existing constraints in more detail:

# pcs constraint --full

Example of a location constraint after a resource move:

      Node: hana08 (score:-INFINITY) (role:Started) (id:cli-ban-SAPHana_RH2_02-clone-on-hana08)

Clear this location constraint:

# pcs resource clear SAPHana_RH2_02-clone

Verify the constraint is gone from the constraints list. If it persists, explicitly delete it using its constraint id:

# pcs constraint delete cli-ban-SAPHana_RH2_02-clone-on-hana08

If you run several tests with fencing you might also clear the stonith history:

# pcs stonith history cleanup

All pcs commands are executed as user root. Please also check Discover leftovers.

Various cluster command examples

# pcs status --full
# crm_mon -1Arf # Provides an overview
# pcs resource # Lists all resources and shows if they are running
# pcs constraint --full # Lists all constraint ids which should be removed
# pcs cluster start --all # This will start the cluster on all nodes
# pcs cluster stop --all # This will stop the cluster on all nodes
# pcs node attribute # Lists node attributes

You have to follow several steps to know what the current status of the environment is. Please refer to Monitor the environment. Also, we recommend to do the following:

# yum info resource-agents-sap-hana
Last metadata expiration check: 2:47:28 ago on Tue 06 Jun 2023 03:13:57 AM CEST.
Installed Packages
Name         : resource-agents-sap-hana
Epoch        : 1
Version      : 0.162.1
Release      : 2.el9_2
Architecture : noarch
Size         : 174 k
Source       : resource-agents-sap-hana-0.162.1-2.el9_2.src.rpm
Repository   : @System
Summary      : SAP HANA cluster resource agents
URL          : https://github.com/SUSE/SAPHanaSR
License      : GPLv2+
Description  : The SAP HANA resource agents interface with Pacemaker to allow
             : SAP instances to be managed in a cluster environment.

# rpm -q resource-agents-sap-hana
resource-agents-sap-hana-0.162.1-2.el9_2.noarch

You can add this to your shell profile. In the example the root aliases depend on the <sid>adm aliases, which must therefore also already be defined.