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Hi colleagues


For a server placed on VMware, I use snapshots with "File system and application consistent" enabled for backup. On this same server is installed MS SQL Server, and also iDataAgen Commvault (iDataAgent) for SQL backup.

During VMware snapshot backup for this server, SQL Server reports to me that at the indicated moment of snapshot execution, 5 seconds later, an additional (in addition to the scheduler for MSSQL for iDataAgent) full database backup is run, which are is not included in scheduler for iDataAgent.

I checked it and this full SQL backup coincides with the snapshot backup called from a separate scheduler with the options set as above. From the SQL side, it can be seen that the Commvault-syndicated backup for the SQL backup is called on the ‘Commvaut Galaxy Backup” user, and the full backup one connected to the snapshot, is executed on the “NT AUTHORITY/SYSTEM” user.

Does anyone know why this is happening, and how to disable the execution of the additional full backup on SQL, called when running the snapshot backup?

 

Best regards

Martin

Hello @Wloski 

Would it be possible for you to exclude the disk on which SQL resides from the snapshot backups?

Best,

Rajiv Singal

Hello @Wloski 

Would it be possible for you to exclude the disk on which SQL resides from the snapshot backups?

Best,

Rajiv Singal

Thank You Rajiv for the advice, but it isn't possible because unfortunately, the subclient in which the indicated server is contained also contains other servers. Since disk exclusion is at the level of the virtual scsi controller and we have no standardization when provisioning servers with MS SQL, it is highly risky to exclude disk backup for the entire subclient.exclusion disk is based on 

Hello @Wloski ,

It seems like a case where in VM backup’s subclient properties, application aware backup is chosen, then along with the VM snapshot based backup it will also initiate the backup of the application hosted on it, can you please verify again for the affected VM in its subclient properties ?

Doc -

https://documentation.commvault.com/2022e/essential/106239_application_aware_backups.html

Hi @Wloski,

 

File System and Application Consistent Snapshots will engage all of the VSS writers on the guest VM (which is why it requires VMWare Tools to perform), so it makes SQL think a VSS backup has been performed.  If you still want to use VSA snaps along with the Agent based streaming backups, then I would recommend using Crash Consistent Snapshots on those machines.  Those will not engage the VSS writers.

Hi colleagues


For a server placed on VMware, I use snapshots with "File system and application consistent" enabled for backup. On this.. /cut.

Hi @Wloski,

 

File System and Application Consistent Snapshots will engage all of the VSS writers on the guest VM (which is why it requires VMWare Tools to perform), so it makes SQL think a VSS backup has been performed.  If you still want to use VSA snaps along with the Agent based streaming backups, then I would recommend using Crash Consistent Snapshots on those machines.  Those will not engage the VSS writers.

Hi Mike

Thank you very much Mike, this does indeed change the backup behavior and solves the problem, but it does not give an answer as to why it happens, because on the same VCenter I have other sub-clients containing sets of machines with SQL server which have the "File System and Application Consistent (Production Checkpoint)" option enabled in VM backup, and yet when performing snapshot backup, operations for them, the full database backup is not triggered.

Would you be so kind as to explain to me what could be the difference (besides the one described) between VMs or, ESX, or Commvault settings that could affect this?

Best regards

Martin

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