The 3580 is the only drive on the 2940UW.  As for cable quality, I have
tried three different cables with the same result.  I even disconnected the
Mammoth2 from the onboard IBM Ultra160 controller and used its cable with
the 2940UW, with the same results.

I originally had the 3580 connected to the onboard Ultra160 controller and
was having poor performance.  IBM support told me that it was not on their
compatibility list so I put in the 2940UW.

With large files (300MB - 1GB) I can push the drive over 40GB/hr,
performance only suffers when the data is smaller files.



-----Original Message-----
From: Dan Foster [mailto:dsf AT GBLX DOT NET]
Sent: Friday, June 13, 2003 8:47 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: TSM LTO 3580 Performance


Hot Diggety! Colby Morgan was rumored to have written:
> The SCSI adapter is a 2940UW.  It does run great with large files, so
> if we had an adapter hardware bottleneck file size shouldn't make a
> difference. We are running the v5.0.2183.1 of the Microsoft drivers.
> I also opened a call with IBM, and they didn't make any
> recommendations to update the adapter drivers.

How many drives per SCSI bus? We limit it to two for a 80 MB/sec SCSI bus
because a single drive is capable of pushing up to about 30 MB/sec in
compressed mode over the SCSI bus.

As a side note - with a diskpool, we achieve about 70-80 GB/sec with our
LTO-1 drives, so the fact you're getting 1/5 to 1/8 the performance does
sound pretty terrible, indeed.

Could it be cabling quality issues - ie, reflection on the bus causing
excessive retries or other related SCSI errors? That's another place where
performance could be killed.

-Dan