We have an LTO-3 Tape drive in a Dell media library that we use for our tape backups. The article about LTO on Wikipedia states that:
LTO uses an automatic verify-after-write technology to immediately check the data as it is being written, but some backup systems explicitly perform a completely separate tape reading operation to verify the tape was written correctly. This separate verify operation doubles the number of end-to-end passes for each scheduled backup, and reduces the tape life by half.
What I would like to know is, do I need my backup software (Backup Exec in this case) to perform a verify on these tapes or is the verify-after-write technology inherent in LTO drives sufficient?
I would also be curious if Backup Exec understands the verify-after-write technology enough to alert me if that technology couldn't veryify the data or will it just ignore it making it useless anyway since even if the drive detecs a problem I would never know about it.
Best Answer
Great question!
Whilst I would say that yes you should test them, I'd say that testing the tapes/drives in themselves is important what is much more vital is testing the end to end restoration process.
I can't recommend enough regular full system restorations and service testing, it's the only way to know for sure that the entire system is doing what you bought it for. You don't have to look far on this site to see people who struggle to restore their service even though they thought they'd covered all the steps individually.
Hope this helps.