DLT1 C7503a slow performance

[Marc Miller_1]

Novell 5 & Arcserve 6.61
Dell Poweredge 2500 & Adaptec 2940 (only tbu on card)
System was working fine with DAT drive. Installed new DLT drive and new cable. Performance is now 6M/min. Swapped cable with no change. Changed settings on the adaptec, no effect.
ANY IDEAS?

[Eugeny Brychkov]

Marc,
was that DAT drive Narrow Single ended? This DLT1 drive should be wide LVD. So maybe if your 2940 is not UW then you should use UW or find SCSI cable with higher data wires terminated. See http://www.hp.com/cposupport/information_storage/support_doc/lpg50063.html
Eugeny

[Dave Unverhau_1]

Have a look at this document, Marc:

http://www.hp.com/cposupport/information_storage/support_doc/lpg50167.html

In particular, the sections on block size and mixing disks & tapes on the SCSI bus might be related to your problem (you mentioned that it's the only tape backup on the card, but you didn't mention if any other devices are on the card.

Also (as Eugeny mentioned), this is a SCSI LVD device. The 2940 may not have enough bandwidth to allow the DLT1 to stream data continuously, and start/stop mode kills performance.

Best Regards,

Dave

[Marc Miller_1]

Thanks for the replies. I tried the drive again.

I turned off wide negotiation (system hangs every time otherwise)

The system hangs when the drive ID is set to 0 or 1 but boots on ID 2.

The system and Novell recognize the drive but not Arcserve. This is the only device on this controller.

Any ideas?

[Lewis Finch]

Marc,

I believe Eugeny hit the nail on the head. The drive is oviously running in single ended mode which is affecting performance. Recommend you use a 29160 card for this. Also I would guess the block size is incorrect in your backup software. change it to 64k and see what happens. You should be getting aroung 3MB/sec with this drive.

[meloni]

having a look at your second comment, probably you have to check for connection problem, try to swapp cable and/or terminator, if the unit is alone on the scsi bus, wide negotation have to work, if it hang when in wide mode, probably some line of the bus is having problem, check also for bent pins in each connector of the cable.