Generally, the performance of the HASS disk subsystems is very good. The
recommendation is fairly standard at 8-10 drives per FWD SCSI controller (8
is more common due to the number of drives a HASS can hold). I have not
implemented any 18GB drives, but the 4.3 and 9.1 GB drives have performed
well.

The issue with the HASS is more of reliability than performance. Since the
disk drives are mass produced by non-HP manufacturers, the drives fail more
oftern than one would expect. Hence, the strong recommendation for
MirroredDisk/iX, which protects the system from crashing due to a disk
failure, plus provides a performance boost for READ activities.

As far as the HP-PB expansion card cage, as I understand, the limit of five
is an "HP support" issue. You can install and run seven FWD cards in a card
cage. I believe the reason that HP supports up to five is a throughput
issue. The bus converter (connects the card cage to the backplane) bandwidth
may not be able to drive seven FWD cards to their documented performance
speeds.

Regards,


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-----Original Message-----
From: Karl Hancock [mailto:[log in to unmask]]
Sent: Wednesday, April 12, 2000 4:54 PM
Subject: HASS performance


I would like some advice about performance of HP's HASS disk subsystems.

What is the recommended number of spindles or GBs per FW SCSI controller?
How does this change if the drives are being mirrored?
Application would be Amisys.

Also is there any concern about performance problems if you have more than 5
FW SCSI controller cards in an expansion bus?