Re: I/O performance problem after change to HP-UX 11.31

On 25 Maj, 23:45, "Neil Truby" <neil.tr...@xxxxxxxxxxx> wrote:
"Ulf" <ulf.akerb...@xxxxxxxxx> wrote in message

news:2f85e555-2db8-4456-8b8c-f63ea068b744@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx







We are using 10.00.FC8 on HP-UX

Moved all our databases from Parisc to Itanium this weekend and are
experiencing that disk io is much slower.

We have exactly the same IDS config, same database layout in both
cases. Data is stored in a SAN (EMC), the new production environment
has a new EMC cabinet, new SAN switches.

As an example a seq scan of a  large table takes about 3 times the
time it took in the old environment. CPU load is not noticable, cache
rate is fine.

We are not using KAIO.

Any ideas that can explain this ?

Are you able to eliminate, or implicate, Informix as the cause by doing some
dd's directly from the RISC and Itanium servers?
eg

time dd if=/dev/zero of=/dev/vg01/rtest1 bs=2k count=1000000

Can you post the results pls?- Dölj citerad text -

- Visa citerad text -

Tests using dd showed that the new environment was much slower. This
was due to the fact that the disks used in the EMC cabinet was slower
that the ones used before.

We have now moved our databases to the other, faster type, of disks.
The result is that we get the same speed using dd as before and the
same IO performance from IDS as before.

Thanks for your input !

Ulf

.

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