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How often should LTO tapes be replaced?

We're getting several CRC write errors on our backups. Does this indicate that the tapes should be replaced?

This batch of tapes has been in use daily since May/June 2003.



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PeteKing
Asked:
PeteKing
1 Solution
 
timbatteyCommented:
Different manufacturers will rate their tapes differently. Usually, the rating will vary depending on whether the tape is in use of shelved for long term retention. Some vendors also rate full passes and tape loads separately.

Eg:

The IBM 3592 tape media is rated at 300 full-file passes, 40000 short length cycles, 20000 load/unload, and 30 years shelf life (under optimal conditions)
LTO tape media is rated at 260 full-file passes, 5000 load/unload, and 30 years shelf life (under optimal conditions)

However you should use these numbers as guidelines as real life use, handling and storage conditions will prevail and life span may be much shorter than advertised.

General rule is this: the first time a write error occurs on a tape media, the situation should be monitored closely. If a write error reoccurs, remaining data on the tape should be migrated and the faulty media replaced.

If a read error occurs on a tape media, all remaining data on the tape should be migrated immediately and the faulty media replaced.

Hope this helps
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Danny ChildIT ManagerCommented:
Are the drives asking for cleaning tapes at all?  Do you keep any logs of when the failures occur compared to which tape is in use (and how old/frequently used it is).  

If you get these errors with new media, and there are no requests for tape cleaning, I'd suspect the drive itself.  Otherwise, you'll need more info as to when the failures occur.

One last thing to consider is the CRC errors themselves - is it possible that the actual files on disk are corrupt?
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PeteKingAuthor Commented:
The drive's aren't asking for cleaning tapes.
The logs show that these errors don't occur at a regular interval (e.g. every Wednesday), which would allow us to pinpoint a specific tape.
Each tape is used once each week on a specific day. They were all setup at the same time. So, they should all have the same wear and tear.

The files could back up to any of 4 drives, but only one (occasionally a second one) gets these errors, which pretty much rules out the files.

I do agree that it looks more like the drive, but the supplier is trying to get us to check everything else out first, before they send a replacement.
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timbatteyCommented:
have you got any newer tapes that you could try? this might shed some light on whether it is the drive or the tapes?

Also what conditions are the tapes stored in?
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PeteKingAuthor Commented:
We can swap in a couple of days worth of tapes and see how they go.

The tapes are stored in a datasafe in an air-conditioned room (cool temperature).
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timbatteyCommented:
Hmm so shelf life shouldn't really be a problem..

I'd try swapping the tapes that might help to determine if its the tapes or the drive.. Then you should be able to relatively easily get a replacement if necessary you'll have tried everything..
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dovidmichelCommented:
cool temp is important too cold or hot and the life shortens.

Brand tapes is important, each LTO manufacture (Certance, HP, & IBM) recommends only specific tapes should be used. Any certified LTO tape "can" be used, but better performance, reliability, and less errors will be experienced if their tapes are used. This is not just marketing talk, it's built in and I've seen the difference at several sites.

Where are those CRC errors coming from?
If the software is reporting them during the verify then perhaps they are not coming from the drive at all. It is possible the data is being corrupted somewhere along the way from the data source to the tape drive.

If the software is ARCserve check the database for read/write errors.
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PeteKingAuthor Commented:
Problem was proved to be with drive. Swapped it out and the errors have gone.
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