SnapCreator Consistency Group Problem:Operation failed: Unknown cg operation.

[volker_albrecht]

Hello,

we make with Snapcreator 3.5.0 hourly offline snapshots with consistency groups. But some times the creation of this snapshots failed with this error message. The next snapshot works with out errors.

In the logfile I found this:

########## Starting Consistency Group Snapshot for <FILER> ##########

[Mon Feb 18 08:00:56 2013] INFO: Starting NetApp Consistency Group Snapshot P82_NFS_local_offline-daily_recent for volumes sap07_nfs_P82 on <FILER>

[Mon Feb 18 08:00:56 2013] INFO: NetApp Consistency Group wafl sync for <FILER> volumes sap07_nfs_P82 succeeded!

[Mon Feb 18 08:00:57 2013] INFO: NetApp Consistency Group Start for <FILER> volumes sap07_nfs_P82 succeeded!

########## Committing Consistency Group Snapshot for all filers ##########

[Mon Feb 18 08:00:57 2013] ZAPI: Operation failed: Unknown cg operation..

[Mon Feb 18 08:00:57 2013] ERROR: [scf-00013] NetApp Consistency Group Commit for <FILER>! Exiting

Regards

V. Albrecht

[ktenzer]

Yeah this isnt an SC problem really. Consistency Group snapshot has a timeout associated to it so this means it took too long.

CG snapshots are a two phase process

1) achieve IO bubble around volumes

2) take snapshots

Both step 1 and 2 need to happen within the CG timeout. You can set this in SC, the options are urgent (2 seconds), medium (7 seconds), or relaxed (20 seconds).

If would update NTAP_CONSISTENCY_GROUP_SNAPSHOT=relaxed in SC that is about all you can do. If it still takes too long then you need to work with NGS and understand why it is taking long. Could be system is under heavy load. Remember we are holding writes in NVRAM for the volumes, this is why we cant hold things forever, we have to commit to volume, and so therefore there is a timeout.

In addition there is a WAFL SYNC option in SC this can help as well to enable if it isnt enabled.

Because there is a timeout and because many things could cause you to not achieve CG snapshot within timeout there is no guarantee like with normal snapshots that the process will work 100% of the time. It depends on a lot of factors.

Hope this helps

Keith