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Faulty drive or not?

Andrew Raison - ECA
Occasional Contributor

Faulty drive or not?

Hi, We've been experiencing read\write issues with new media. The drive is a LTO4 one and we always use HP media. I've installed the HP L&TT and upgraded to the latest firmware. The drive assessment test reports to have PASSED and the drive is GOOD but the overall drive margin is 59.7%, worst-case margin is 11% and worst-case channel variation margin is 99.7%. This was with a new tape. If I do the same test with a tape that has been overwritten several hundred times then overall drive margin is 92.7%, worst-case margin is 89.2% and worst-case channel variation margin is 99.8%. Very different results! but what does that mean? is the drive on its way out or are they dodgy new tapes? I can't run the media assessment as the drive didn't pass with sufficient margin. Any help appreciated. Andrew
2 REPLIES
LTT Team
Valued Contributor

Re: Faulty drive or not?

Hi Andrew,
please install latest L&TT version which is 4.12 and run a drive assessment test with the new tape and send event log to LTT mail box which is ltt.team@hp.com
Richard Bickers
Trusted Contributor

Re: Faulty drive or not?

Hi Andrew. There will always be some media variation, even with new media, but the drives usually have quite a bit of margin and can cope well with that. Anything over 0% in the assessment test output is pretty good and still has plenty of additional margin over the level at which it might fail. You'd need to see more like <-100% margin in the LTT output before it will give a hard failure.

There is some recently released firmware (for standalone LTO 4) which offers some additional improvements to the drive to handle media variablity so I would recommend an upgrade at this point but, having said that, your test results show that the drive should not be giving any issues during normal backups.

Can you pull and attach a support ticket (or send to LTT.team@hp.com) so we can see your drive history? If the drive or media was the cause of the backup failures then the error code should be in the ticket (under drive history -> errors reported to host). That would be a good place to start.
It's more interesting when it's gone wrong