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pmcdonald

How to verify a very large backup set

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One of the scripts I run is a nightly backup to add any new or altered files to a tape set. The backup set now spans about 70 LTO5 tapes, 100TB of data and several thousand snapshots.

All well and good so far. The catalog is surprisingly quick to index and compare too.

My only issue is some of the earlier tapes are getting on in age now and I'll like some way of verifying and retensioning them from time to time to get a heads up when the tape age is starting to become an issue. I'd do this via the 'Verify' job but it would take about 3 solid 24/7 months to complete, assuming someone was around to baby sit it and swap tapes and the Windows machine didn't restart at any point during that process (it has been known to). We only have one tape deck so that also ties up the backups for that time.

Is there any way around this? Can I selectively verify specific tapes rather than files? I don't want to split the catalog up as some active jobs really do predate this script.

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You could set all tapes except one as "lost" and verify that tape. After the verify you set all the tapes to "found" again.

What if you must do a restore? (After a hard disk failure, for instance.) If you are unlucky, there is (at least) one file on each tape, so it would take "about 3 solid 24/7 months to complete".

I suggest you start a new backup set and keep the current set somewhere safe. 

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Hi Lennart,

Thank you for the quick response and the solution. I hadn't considered marking the other tapes missing but it's a good lateral solution, cheers!

In the event of a volume failure we have a mirrored NAS that can be swapped over with replicated content. If THAT volume failed as well (and both are RAID6, so that would be quite unlucky) I'd cherry pick the specific priority active jobs we needed to continue working while slowly restoring the rest later.

This backup script is typically more for the odd missing file from older projects and files that are accidentally deleted or overwritten. One recent example is on restoring a large design project we found a few missing assets that lived in another now deleted job. I was able to select those specific files from the catalog, relink and continue working.

I think of this backup set as the rings on a tree trunk - it gives us a complete historical copy of every modified and added file over the better part of the last decade and has saved us on a few occasions.

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15 minutes ago, pmcdonald said:

In the event of a volume failure we have a mirrored NAS that can be swapped over with replicated content

Excellent. :) 

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