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theboyk

Rebuild a large catalog file while still backing up?

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Hello.

 

One of my catalog files has become corrupt. It's 3-member LTO4 catalog. Rebuilding is S-L-O-W and it's going to take over 24 hours to rebuild from the three LTO4 tapes. Problem is, during this rebuild, the nightly backup won't run. I was hoping to could "pause" the rebuild, let the backup run, then return to the rebuild, but this doesn't work. Anyone have any suggestions? Could I rebuilt each tape, one at a time (i.e., break the 3-tape catalog somehow into 3 separate catalogs)?

 

Thanks,

Kristin.

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If you have "Fast catalog rebuild" enabled, you only need to run the last tape. The catalog file for the first two tapes is at the beginning of the third tape.

 

If not, You could say "no" when retrospect asks if there are any more tapes. Then after the backup, you could "update" the catalog file with the next tapes.

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Come to think of it: You are not backing up to the same media set as the one you are recreating the catalog file for, are you? Then you would have to wait until you have fully recreated the catalog file before running a backup.

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Nope, not backing up to the same media set, so all good there.

 

And I just checked, and Fast Catalog Rebuild was checked for the Media Set with the corrupt catalog (it's checked for all my media sets, thank goodness—never knew what that was for, until now!) So, you're saying, when I go to Rebuild the Media Set (with the corrupt catalog), all I need to do is point it at Tape 3 in the set (the last tape in the set) and let it do it's thing using that one tape? I don't need to worry about starting the rebuild with the first tape in the set?

 

And just for my own knowledge—if I didn't have Fast Catalog Rebuild checked and I needed to do it per-tape in the set, thus started with Tape 1, how would I do about "updating" the catalog with the next tape (after saying "no" to "any more tapes" at the end of the first tape rebuild)?

 

Thanks,

Kristin.

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That was a lot of questions. :)

 

Yes, you should "let it do its thing" using the last tape only.

No need for the first or second tape.

 

Sorry, It says "Repair" in the Mac version of Retrospect. In the Windows version I'm pretty sure it says "update".

So, after aborting the "recreate" after the first tape, you should "repair" the media set and insert the second tape.

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I'm puzzled. Why would Retro refuse to do a backup because a rebuild was in progress? If the destination of the backup set is different from the media set that is being rebuilt, then I would not expect them to interfere with each other.

 

Is Retrospect constrained to a single execution thread. (you can change that in prefs)

 

Do tell...

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Lennart: Worked like a charm, thanks. Fast Catalog Rebuild for the win! Wondering, why wouldn't you want to use Fast Catalog Rebuild?

 

iCompute & Lennart: Yes backups go to LTO4 tapes, and even though I have two individual tape drives attached to the server (handy, for keeping a blank tape available incase the current tape fills up mid-backup), out-of-the-box, Retrospect only supports a single drive being used at any one time. Parallel drive usage is an extra fee/upgrade (which, until now, I've never needed in 10+ years of using Retrospect with tape drives).

 

Anyway, the catalog has been rebuilt and we're all good again! Next up...upgrading Retrospect...maybe.

 

Thanks again!

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Lennart: Worked like a charm, thanks. Fast Catalog Rebuild for the win! Wondering, why wouldn't you want to use Fast Catalog Rebuild?

 

 

You are welcome. :)

 

I think that in the past with maybe 50GB tapes, you don't want a 20GB catalog file in the beginning of each (of the higher-numbered) tape for a large media set.

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Does the "fast catalog rebuild" apply to "disk" sets as well - putting a copy of the catalog at the front of every "member"?

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Does the "fast catalog rebuild" apply to "disk" sets as well - putting a copy of the catalog at the front of every "member"?

I think it does. But I don't think it works with grooming.

The keywords here are "I think". Better check the manual. :)

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But I don't think it works with grooming.

Don't know about that, but I do know that grooming is not so useful for multiple-member disk sets. Although Retrospect will groom out the earlier backups, the space recovered on the earlier members cannot be reclaimed, as Retrospect will only write to the last member and you can't move backup files from one disk volume to another. Grooming is really only effective for a single volume media set.

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