What to do when recatalog has errors?

[oslomike]

I have been recatalogging old backup sets and in doing so there seems to be some errors where it can't read the tape. I know that all of the tapes were verified at one point during their backup lives (btw, tapes only get written to once, I don't reuse tapes), but after the recatalog and the incurred errors the some files were missing when I restored a big project. SO, what are my options other than sending the tape off to a very expensive data recovery place? Are there any "Retrospect Friendly" software tools (similar to Tolis' Tape Tools) that can read tapes an save the files to disk?

 

As far as trouble shooting, I have tried different drives and I've tried recataloging a couple times over the same tape. Still I get errors. I did clean the drives with the cleaning tape as well.

 

Any help is appreciated!

 

Thanks!

Mike

[Lennart_T]

What errors do you get?

 

How many tapes have you tried? How old are they? How have they been stored?

[oslomike]

Hi lennart! Tapes have been stored in a big safe and are from 2009. I have tried other tapes but I haven't checks those for errors. I suspect that they also had errors.

[twickland]

In my experience, certain tape types (DAT, say) are more likely to incur errors than others (LTO). We always retain three independent backups on DAT tapes and two on LTO to improve our chances of bridging through a read error on a particular tape.

 

If you're getting errors at the same point on a tape member when using different drives, that's pretty diagnostic of trouble with the tape itself. Have you tried recovering the missing files by a direct search rather than a snapshot? Sometimes this seems to work better. You may also be able to retrieve a slightly earlier version of the file that may be better than nothing.

 

FWIW, we've found that rebuilding a catalog in Retro 6 is a fastidious process that sometimes flags errors that may not affect retrieving a file using the original catalog. We therefore retain multiple copies of old catalogs so we can avoid performing a rebuild. Sometimes, though, a tape will get hosed for no obvious reason, such that it refuses to read a file past a certain point. While it can't retrieve that particular file, if you then search for a file that was witten to the tape at a later time than the affected file, the later file (and subsequent files) can often be retrieved. Thankfully, Retro 6 enables one to easily search the catalog based on backup date/time, making this kind or workaround a practical option.