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What is required to Snapshot a volume that hold a SQl database and use VSS

RMoore_1
Occasional Contributor

What is required to Snapshot a volume that hold a SQl database and use VSS

I am a bit confused on what is required to guarantee Database Integrity when taking a snapshot of a volume that holds a SQL database and logs. My scenario is I have multiple Windows servers that run SQL, each server has an ISCSI volume to the SANS. The volumes hold the servers SQL databases and log files.
I have installed the HP LeftHand P4000 VSS Provider from the Windows Solution Pack on each server. No other software at this time is on the servers such as Backup software. What do I need to do on the WIndows side and the SAN snapshot side to use VSS and make sure that the SQL database is quiesced and the Snapshot is good for recovery purposes. We are running SAN-IQ 9.

Thanks
Ray
3 REPLIES
Paul Hutchings
Super Advisor

Re: What is required to Snapshot a volume that hold a SQl database and use VSS

My understanding is that so long as you're using the LH VSS provider you simply install it and configure the credentials and then when you use the CMC to take a snapshot it's quiesced/consistent.

How this ties in with your backup software depends on your backup software I believe.

Have you read c01865547.pdf?
RMoore_1
Occasional Contributor

Re: What is required to Snapshot a volume that hold a SQl database and use VSS

Hi Paul

Thanks for the reply, What you are saying is what I thought also. I had HP lefthand support sessioned in looking at another issue and he noticed that we are backing up SQL databases. He stated that just installing the HP LeftHand P4000 VSS Provider was not enough. He said we needed to use an application assist such as Backup Exec etc to enable the feature and also enable the application assist checkbox on the snapshot configuration tab. I cannot find any specifics anywhere on exactly what you need to snapshot SQL using the VSS provider. He could not eleborate more as he stated that another support tech was more familiar with that feature. But he was pretty adamant that just installing the VSS providor would not do it. So now I am worried that we are not getting consistant database\log files snapshot's.
Paul Hutchings
Super Advisor

Re: What is required to Snapshot a volume that hold a SQl database and use VSS

I'm sure someone will correct me but this is how I understand it.

Let's assume databases on E: and logs on F:

When you create a snapshot within the CMC Windows/SQL quiesce the logs so that when you snapshot the LUNs that are mapped to E: and F: within Windows, they are snapped cleanly so that you could mount them on a server and startup SQL in a consistent state.

If you're using, say, Backup Exec to backup your SQL server, if you're not doing a backup with a SQL agent you're left doing a file level backup of E: and F: and I'm not sure if you use VSS (if Backup Exec has that option) that it would touch the P4000 VSS provider.

What I believe you can do somehow is to have your backup software initiate the backup, it tells the P4000 to take a snapshot, the snapshot is what's then backed up.

I'd be interested to know the nitty gritty on this myself tbh as I'm shortly to be in a similar position.