I have an IBM Netfinity 7000 M10 and I am trying to get my head wrapped around it's SCSI disk system. I am not very familiar with SCSI systems although I have done a good deal of reading on the subject.

System: RedHat 9.0
Machine: Netfinity 7000 M10
RAM: 2 GB's
CPU Info: 4 - 400Mhz Xion
SCSI Controller: ServeRaid 3H Ultra 2

The ServeRaid 3H card supports data transfer rates of 20MBps, 40MBps, and 80MBps. I have tried all sorts of configurations within the SCSI controller and haven't seen transfer rates better than 28 MBps using "hdparm -t".

Is this good? Bad? This server is sitting idle with nobody by myself logged into it. The drive I am testing at the moment is an Ultra3 36.7 GB 15,000RPM LVD/SE drive. I would assume I would get a better throughput rating than this...

Anything you can throw my way to enlighten me about SCSI disk opimization?

In some of my further reading I found this on IBM's website:

SCSI-2 allows for 10MBps (8-bit Fast, or 16-bit Wide SCSI-2 devices), 20MBps (16-bit Fast/Wide, or 32-bit Double-Wide SCSI-2 devices), or 40MBps (32-bit Fast/Double-Wide SCSI-2 devices) data transfers between the controller and SCSI-2 devices designed to operate with those adapters.

Fast? Wide? Fast/Wide? Double-Wide? Fast/Double-Wide?

What are they talking about here? Did the people on the SCSI standards committee live in a Trailer-Park and watch a lot of NASCAR?

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