Very Computer

by **Ume dandike** » Sat, 17 Oct 1998 04:00:00

Is their any utility/command I can use
to determine if there is a disk performance
problem. I did notice a high
disk service time in the iostat report?

No error messages reported by root and
I have now turned on all debugging logs.

Any suggestions to rule out disk error/
performance???

Thnx in advance

Ume

by **sami** » Sat, 17 Oct 1998 04:00:00

Ume,
Performance depends on the Disk configuration(RAID ,SSA etc) and the
SCSI interfaces and the Model of the machine(Iam sure you know that).
Just iostat will not be enough to trace the disk performance issue .If
you see too much pagein page out in vmstat then you might have to
distribute your Paging space acroos VG or PV's.USe vmstat,iostat and SAR
commands in sync and try to get a feel of which part of Disk is causing
the performance bottleneck.
It is advisable to keep your jfs logs(which is accessed the most ) in a
different disk then some of your application(maybe say Oracle ).So
identify the bottleneck and distribute your applications.
-samit

> Is their any utility/command I can use
> to determine if there is a disk performance
> problem. I did notice a high
> disk service time in the iostat report?

> No error messages reported by root and
> I have now turned on all debugging logs.

> Any suggestions to rule out disk error/
> performance???

> Thnx in advance

> Ume

by **AIXMight** » Thu, 22 Oct 1998 04:00:00

Ume,

>Is their any utility/command I can use
>to determine if there is a disk performance
>problem. I did notice a high
>disk service time in the iostat report?

depending on the oslevel you have, you can check /usr/sbin/perf/,
/usr/lpp/*perf*, filemon, fileplace and so on to help you gathering some
stats...

Quote:>Any suggestions to rule out disk error/
>performance???

yea but i'd better refer you to Frank Waters' Performance Tuning Guide.
or you can try the online one at
http://www.rs6000.ibm.com/doc_link/en_US/a_doc_lib/aixbman/prftungd/t...

Orphy! :-)