DASD I/O performance VM 44 vs. VM 52
(too old to reply)
Barton Robinson
2006-03-15 12:34:00 UTC
If you were storage constrained below the 2gb line,
then your dasd performance could be many times better
moving to z/vm 5.2.

>Date: Wed, 15 Mar 2006 13:21:58 +0100
>From: Stefan Raabe <***@deutsche-boerse.com>
>from a Linux point of view, will a VM 5.2 give significant
>better dasd I/O performance than a VM 4.4 system?
>I tried to find some values in the z/VM performance report, of
>course it is better but its hard to find hout how much (10%,
>20%, 50%, ...... ? ?) because most comparison is between vm 5.1
>and vm 5.2.
>Any thumb-rules (or other hints) on this one?

"If you can't measure it, I'm Just NOT interested!"(tm)

Barton Robinson - CBW Internet: ***@VELOCITY-SOFTWARE.COM
Velocity Software, Inc Mailing Address:
196-D Castro Street P.O. Box 390640
Mountain View, CA 94041 Mountain View, CA 94039-0640

VM Performance Hotline: 650-964-8867
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Rob van der Heij
2006-03-15 14:39:06 UTC
On 3/15/06, Stefan Raabe <***@deutsche-boerse.com> wrote:

> I now read about the emulated FBA on SCSI that cones with vm 5.1 which gives some
> improvement in comparison with vm44, but there are no more i/o improvements in the vm 5.1
> performance report.

You don't want to do FBA emulation on SCSI if you are concerned about
I/O performance. That has not been the focus area for this support.

Rob van der Heij
Velocity Software, Inc