On Friday, Jul 9, 2004, at 01:36 Australia/Sydney, asr AT UFL DOT EDU wrote:

==> In article
<OFD41C28C7.910E9B0E-ONCA256ECB.001EBECF-CA256ECB.0021432F AT db DOT com>,
Gordon Woodward <gordon.woodward AT DB DOT COM> writes:

Best recommendation:  try to keep your volumes on a 1:1 basis with your
physical spindles.  It's the best possible way to convey to TSM what
the
architecture of your underyling disk is.

With any disk and controller technology that supports command queuing
(SCSI2 command tagged queuing, SATA Native Command Queuing (NCQ)),
you are better off with about 3 volumes per spindle for random I/O.
TSM serialises I/O per volume, meaning only one I/O in flight to
each volume at any one time.

This is backed up by tests I've run, and is recommended by one of
the IBM TSM support guys here in Australia.

Cheers,
--
Paul Ripke
Unix/OpenVMS/TSM/DBA
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