Question

VM Backups SQL VSS Writer

  • 29 April 2021
  • 4 replies
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Wondered if can anyone tell me if a “file system and application consistent” VM backup of a SQL server where the SQL VSS Writer is enabled utilises the “copy only” backup method so as to not affect any currently configured backup chains?

Thanks


4 replies

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Tom, 

 

Short answer No copy only is not utilized.  The File System and Application Consistent backups will indeed query the vss writers present on the server.  If you want a true SQL backup to be able to utilize the SQL restore functionality I would suggest using the Application Aware option. This will query the VSS writers on the machine and save the meta data for the shadow producing a proper SQL backup.  You would then be able to leverage commvault for the restore SQL functionality.  For more information on this see the links below. 

 

https://documentation.commvault.com/commvault/v11_sp20/article?p=14241.htm

 

https://documentation.commvault.com/commvault/v11_sp20/article?p=14283.htm

 

Thanks,

Chris 

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Hi Chris,

in this scenario the SQL backups are being done using a different method but I am needing protect the virtual machine to allow restore. If required, after the restore of the vm the SQL dbs can be restored from the appropriate backup.

my concern is in the backup phase of the VM it triggering the sql vss writer breaking the other backup methods backup chain.

Assuming Commvault (which is what I’m looking to get confirmation on) isn’t the VSS “requester” and instead VMWare (tools) is, the documentation from VMWare I have read indicates the use of backup type “VSS_BT_COPY” which would mean:

  • Copy Backup (VSS_BT_COPY)—like the VSS_BT_FULL backup type, files will be backed up regardless of their last backup date. However, the backup history of each file will not be updated, and this sort of backup cannot be used as the basis of an incremental or differential backup.

https://code.vmware.com/docs/1674/virtual-disk-programming-guide/doc/vddkBkupVadp.9.6.html
 

https://docs.microsoft.com/en-us/windows/win32/vss/vss-backup-state

 

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Tom,

 

Best option would be to remove the VSS writer from being quesed during the backup.

 

https://kb.vmware.com/s/article/1031200

 

Thanks,

Chris 

Userlevel 4
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Tom,

 

Best option would be to remove the VSS writer from being quesed during the backup.

 

https://kb.vmware.com/s/article/1031200

 

Thanks,

Chris 

 

Thanks, this is also interesting :)

 

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