SAN v SQL Server backups

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SAN v SQL Server backups

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Fraggle-805517 SSCrazy Eights Points: 8907 More actions · Answer 1

Eddie,

Great write up. That gave me a lot of information that I had been looking for.

By chance is this documented somewhere so I can read more on it, or is this just from your personal experience.

Thanks,

Fraggle

Fraggle-805517 SSCrazy Eights Points: 8907 More actions · Answer 2

Jeffrey,

Thanks for the suggestion. That is exactly what I did.

Fraggle

Michael Valentine Jones SSC Guru Points: 64818 More actions · Answer 3

That is exactly what I would expect in a hosting environment.

I have yet to encounter a hosting vendor that had any real knowledge about backup and recovery for SQL Server.

Irish Hall of Fame Points: 3958 More actions · Answer 4

Eddie: Awesome writeup! It nice to have this forum because I learn tons more about SANs and such. Oh, and point taken regarding recoveries saving jobs over backups. It is kind of what I meant, but not what I said. I would add that recovery plans are only as good as the time you have successfully tested them.

Fraggle: I'm glad it worked out in the end. Your story is soooo typical of what I see every single day :crazy: .

The funny thing is, you'd think that a hosting company would have all of this together! How in the world do they make any money?

Regards, Irish

Eddie Wuerch SSChampion Points: 12535 More actions · Answer 5

Fraggle-805517 (10/2/2009)
Eddie,
By chance is this documented somewhere so I can read more on it, or is this just from your personal experience.

I just threw that together as an answer to the question. If it were written up somewhere, I'm not sure I'd even know how to search for it, although a likely location would be in a SAN vendor's documentation, provided they have a VSS solution for SQL Server. Given that those vendors charge a hefty premium for their particular VSS-based SQL Server snapshot/backup software (SQL Server, the OS, and the SAN all have to work together through VSS to pull off a sound snapshot), they will likely point out the limited value of taking snapshots without VSS.

We went into our last SAN vendor selection already having that knowledge, so instead of getting the hard sell for the additional software, we just had a lot of questions surrounding 64-bit support, quiesce times, snapshot-mounting restrictions, ease and ability to automate mounting of snapshots, etc. (...and then we went with a clustering solution that prevented snapshots 🙁 )

Edit to add:

Additionally, many SANs have the ability to replicate from one SAN to another. Gets the data off of the SAN. Fits in the list similar to moving the data to tape; a raw snapshot is not crash-consistant, VSS snapshots still need log files for forward recovery etc. The big difference is speed and availability: the replicated images (of the VSS-based snapshots) can be brought online and rolled forward very quickly, when compared to digging up tapes, copying files off of them, etc. SAN replication really ratchets up the complexity, at the benfit of significantly reduced downtime in the event of catastrophic failure.

Also, adding one more time:

Snapshots are not backups!

Eddie Wuerch
MCM: SQL