Cloning or Staging from Disk to Tape is slow on 1 drive

[spookeyx]

We are running Networker 6.1.1 on Compaq ML530 and ADIC Scalar 1000 Tape Library w/4 DLT8000 drives. Drive 0 writes about 1/10 the speed of the others when cloning or staging to tape from disk. Has anyone else seen this?

I have checked/changed the SCSI adapters and controllers; even changed the drive.

Thanks,

Bill Barksdale

 

[rgzimmer]

We have replaced a total of three of our DLT8000 drives in two months due to a faulty chip on the controller board in one of the library modules.

The indications that something was wrong: Frequent cleanings required and slow write performance.

You may also have a faulty power supply on that drive.

 

[spookeyx]

What is weird about this, is that if I backup to tape the speed is fine. It is only slow when I clone or stage..... The other 3 drives have no problem.

Thanks

 

[MoshiachNow]

I would also use some perfomance tools to check what is going on during cloning on this drive.
Any process stuck?
Are there tape errors in the system log?
Is there a lot of paging going on - more memory good help ? "Long live king Moshiach !"

 

[cptb]

Cloning is generally a very slow process. Most cases you can't compare it with backup performance. That is true for both disk and tape reads. So I should think that what you're seeing is normal.