I love the new verify feature - but i have a question

[mkretzer]

Hi,

we are in the process of bringing a new tape library into production. Previously we just trusted a new device to be "good" as restoring all our production tapes would need 100 TB avaiable somewhere.

With the feature i found out that the new library seems to have one defective drive - fresh tapes, only written once show CRC errors every 15 TB or so, only on one of the drives. I would have never found this so easily without the verification.

The one thing i wonder is why only one drive of the tape library is used when multiple tapes are selected...

Markus

[Egor Yakovlev]

Hi mkretzer

Thanks for warm feedback, glad you liked the feature!
As for the drive usage - verification job picks a drive to use at start and sticks to it by design. If you want to utilize several drives, just start several verifications in parallel!

/Cheers!

[Moopere]

With the feature i found out that the new library seems to have one defective drive - fresh tapes, only written once show CRC errors every 15 TB or so, only on one of the drives. I would have never found this so easily without the verification.

Mmm. Modern tape drives almost always have a write then verify internal to their own mechanism, which should then be reported back to the software. I would expect a bad drive to show up even without external verification. Are you sure there isn't some data corruption going on somewhere or somehow in the data path from the drive back to the backup machine?

[mkretzer]

Might be. The drive also showed the error ("i can no longer read from this tape") so it is unlikely. The FC adapter is directly connected so the path is not that long.

[Dima P.]

Hello Markus,

Thanks for the feedback! Mind me asking what tape drive/library model you are installing?

[mkretzer]

Quantum i3 with LTO8

[Dima P.]

Thanks! Have not heard anything bad related to this device from support or RnD, so might be a hardware issue. Does Quantum provide any drive diagnostic tools to identify the drive misbehavior?

[mkretzer]

We got a new drive from them. Testing now...