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Fail-Over Cluster

anvardheen_jabarullah
Participant
0 Kudos

Hi,

We ahve PRD server in Cluster environment.If cluster fails , node will be moved from one node to another?

At that time, What are the actions  taken from BASIS?

Accepted Solutions (1)

Accepted Solutions (1)

Former Member
0 Kudos

Hi....

Please use this link.you will get more idea and you will know about actions  taken from BASIS.

http://help.sap.com/saphelp_nw04/helpdata/en/08/5744e44ae611d1894f0000e829fbbd/content.htm

Regards,

Prabaharan B

Former Member
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Hi...

read this link

http://scn.sap.com/docs/DOC-25454#section7

Regards,

Prabaharan B

Answers (3)

Answers (3)

chad_patrick
Explorer
0 Kudos

Dheen AJ,

This is a very good question. 

  1. Ensure that the Application comes online in the new cluster.
  2. Check the SAP Management Console to make sure that all instances are green.  Pay special attention to processes which may be failing.  SAPCPE.EXE comes to mind and frequently problematic.
  3. If both of these check out, your cluster fail over has work successfully. 

I would suggest that you periodically check your cluster by switching over in a planned operation.  When doing this you can monitor your enqueue replication and see that it is functioning properly. 

Here is a good reference.

And an Excerpt from another blog.

Monitoring the Lock Table at Failover

Use program enqt to check the fill level of the lock table and the failover ID. The SCS instance of the SAP system has been started.

Start program enqt on the server on which the replication server is installed. Then use the enqt options described here. Otherwise you could damage the content of the lock table.

Monitoring the Fill Level of the Lock Table at Failover

...

  1. 1. Enter the command below to fill the lock table of the enqueue server with 20 locks: enqtpf=/usr/sap/<SID>/SYS/profile/<SID>_ERS11__<hostname> 11 20
  1. Monitor the fill level of the lock table by executing the command:

enqt pf=/usr/sap/<SID>/SYS/profile/<SID>_ERS11_<hostname> 20 1 1 9999This command permanently reads the content of the lock table and shows the number of lock entries on the

  1. console.

Monitoring Lock Table ID at Failover

...

  1. Enter the following command on the ERS host to output the lock table ID before the failover:

enqt pf=/usr/sap/<SID>/SYS/profile/<SID>_ERS11__<hostname> 97

  1. Trigger a failover of the SCS instance.
  1. Enter the command

enqt pf=/usr/sap/<SID>/SYS/profile/<SID>_ERS11__<hostname> 97The output for the row containing EnqTabCreaTime/RandomNumber should be exactly same before and after failover should be different .

  1. Make sure that the lock table ID is the same before and after the failover. If it isn’t, the replica has not been copied .

4. Commands to check status of ERS/SCS instances

To monitor the status of ERS/SCS instances, the commands described below may be used (for example in HA scripts):

ERS Commands

To determine the replication server enter the following command:

  ensmon pf=/usr/sap/<SID>/SYS/profile/<SID>_ERS11_<hostname> 2

If replication server is active and connected to SCS, the following message is displayed in the first few lines of the output:

  Replication is enabled in server, repl. server is connected

  Replication is active

The status may also be checked with the command "startsap check", however, this command seems to check only the process at the OS level, not for the functioning of the process.

SCS Commands

Send a dummy request to the server, to check if it is alive:

  ensmon –H < scshostname> pf=/sapmnt/<SID>/profile/<SID>_SCS04_< scshostname>  1

Last line of output contains the message "Dummy request executed successfully with rc=0

The status may also be checked with the command "startsap check", however, this command seems to check only the process at the OS level, not for the functioning of the process.

Former Member
0 Kudos

well, not the node will be moved (failing over) but hopefully some Windows Cluster Groups.

>>At that time, What are the actions  taken from BASIS?

That depends on the version of your SAP release.

former_member182034
Active Contributor
0 Kudos

hi Anvar,

please check the point#10 from below SAP note, hopefully, it might be helpful.

Note 112266 - SAP and MS Cluster Server: Frequent questions and tips

Regards,