Video Screencast Help

Replication Stop - in DCM Mode

Created: 29 Jan 2013 • Updated: 29 Jan 2013 | 8 comments
Faisal Saleem's picture
This issue has been solved. See solution.

I am having replication configured from Primary to DR Site on Windows, today I have faced an issue where replication was stop and in DCM Mode.

What I did to resolve was started resync secondaries and everything started from scratch and things got replicated.

I would like to know what are the possible reasons when this issue occurs, and do I have any another solution to resolve this issue besides resyncing.

Will be thankful for some positive response

Comments 8 CommentsJump to latest comment

mikebounds's picture

If the SRL fills up, VVR stops transferring data and tracks changes in the DCM.  To resume replication you can resync using only the changed regions tracked in the DCM using:

vradmin -g diskgroup resync RVG-name

The secondary will be inconsistent during the replay as the writes are not replayed in the order they were written as they are when draining the SRL.

The DCM is also used if you takeover at your secondary, while the primary is down and when the old primary comes back you then have a primary-primary config using DCM.  To resume repliation in this case use:

 

vradmin -g diskgroup fbsync RVG-name

Mike

UK Symantec Consultant in VCS, GCO, SF, VVR, VxAT on Solaris, AIX, HP-ux, Linux & Windows

If this post has answered your question then please click on "Mark as solution" link below

SOLUTION
Faisal Saleem's picture

Thanks mike for your quick response.

I would like to clear my self little more therefore I would like to ask you few more questions with respective to your reply.

vradmin -g diskgroup resync RVG-name

The above command is equally same as logging into VEA (GUI) and clicking resync secondaries ??

============================================================================

Further if I ever enconter a issue of primary-primary config and use fbsync, what will be the actual affect of fbsync ? which node will be primary then ?

and all my data will be 100% replicated on both nodes ?? what if data is left in SRL ?

mikebounds's picture

Yes, vradmin resync is the same as logging into VEA (GUI) and clicking resync secondaries.

Fbsync will make the orginal primary a secondary, so the new primary will remain primary (where you did the takeover) and the fbsync will use DCM replay as in resync command (and there will almost certainly be the option to do this in VEA too).

When the DCM is used, all the writes in the SRL are converted to regions in the DCM.  When DCM replay is complete you are 100% replicated and then replication continues using SRL.

Mike

UK Symantec Consultant in VCS, GCO, SF, VVR, VxAT on Solaris, AIX, HP-ux, Linux & Windows

If this post has answered your question then please click on "Mark as solution" link below

Faisal Saleem's picture

Thanks for the response again, Yes now I am clear with my conceptional issues.

After the 100% replication, I can revert back the status of New Primary back to Secondary right ?

 

mikebounds's picture

Yes, after DCM replay completes you can run "vradmin migrate" or reverse roles in VEA.

Mike

UK Symantec Consultant in VCS, GCO, SF, VVR, VxAT on Solaris, AIX, HP-ux, Linux & Windows

If this post has answered your question then please click on "Mark as solution" link below

Faisal Saleem's picture

Thank you mikebounds, it was nice discussing issues with you and your replies were frequent, positive and clear.

Nice to have support from you :)

mikebounds's picture

I'm glad I could help - if you are happy with solution, then please mark the post that helped you the most as the solution.

Mike

UK Symantec Consultant in VCS, GCO, SF, VVR, VxAT on Solaris, AIX, HP-ux, Linux & Windows

If this post has answered your question then please click on "Mark as solution" link below

Faisal Saleem's picture

Sure that would be my honour, Marked as Solution :)