Deduplication and storage of backups

  • While at PASS this year I heard that it was a bad idea to have your backups on deduplicated storage. The reason was that if a single block was lost or corrupted beyond repair, you could loose multiple generations of backups if they all shared it in common. I've tried to search for more information, but I haven't found anything that directly addresses this. When I asked the SAN guy he said not to worry as it did some sort of parity calculation to allow for recovery in case of corruption, and this wasn't a concern. At any rate the SANs are geographically mirrored so that there is at least one other copy. Still, I can easily see a nightmare scenario with a corruption and crash magnified by us being in an auto-tiering configuration.

    Anybody have any advice or know of any resources that discuss this? Thanks!

  • I don't know of a specific resource.

    A lot of people are scared (semi-justified) of data deduplication. It's a somewhat new technology and it can be a little sketchy, but I'd say it's no more dangerous to use than any other storage mechanism. Database backups can be corrupted by any number of things, not just dedupe. Dedupe just adds another to the list. So the rules are still the same. Take your backup, test your backup, but, have a second copy off-site on a regular basis to some other storage location.

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  • Thanks! I'm going to see if we can add a third place where we can keep a set of backups as you suggested.

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