We are using RHEL(4ES) and tandberg 20/40 40gb tape drive. We have 40gb capacity tapes for backup. Can anybody tell me what precautions we have to take when taking sys backup? sometimes the tape is not writing anything and we donot know whether backup is taken or not. To counter this we are using tabulation method, which verifies the data after backup.

What are the general errors come when taking tape drive backup?

Thanking you all...

I used tape backups for several years. If you are using compression then the long pauses are possibly caused by the CPU being slower than the tape drive. Compression takes a lot of CPU time and it is possible for the tape drive to be idle while the CPU is still busy compressing the next block of data.

The general error that surprised me with tape backups is the need to retension the tape once in a while. If the tape stretches then you can end up with backup tapes that are not readable. So once in a while you have to retension the tape before you do the backup. Some tapes need to be reformatted after you retension them.

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Steve Stites

P.S. All of the problems I had with tape backups occurred during recovery. There were the stretched tapes not being readable. Another problem is that when you only want to do a partial recovery you can spend a long time reading down the tape to find the little bit of data that you wanted to recover.

With regard to Jailbait's P.S. -- always, always, always, test your backups by doing a recover. This is especially important as you are getting started, but should be done periodically on production systems as well. Depending on what applications you are using to do backups, you may just need to check an index of the tape, pick some file you want to recover, and do that. But you should also confirm that you can pull back the whole thing. Use a test partition.

Backups are easy if you don't need to recover . But, the whole point of doing backups is so that you can recover. Make sure that's true in your case. Be sure, not just that the tapes work, but that you are familiar with the steps and can do them quickly and easily when you are in a panic. For example, if your system is blown away, and you have to boot off a CD and recover from tape, can you do that?