[Ran]

Hi All,

Wondering if I can get some direction as to what to do next.

I have a filesystem that is producing 100% disk busy and only writing 4Mb/Sec max. TPS is 330 peak with a size of 12K average. The data has it's own disk and the jfslog is on a seperate hdisk.

The data is temporary files for Sonic ESB/MQ Application

I've tried tuning memory and jfs2 options via vmo and ioo. But not had a major impact. Also tried disk pacing.

Would DIO/CIO help or would it be better if I just put the filesystem on SAN storage?

Cheers

Ran.

[Mark Taylor]

>> Would DIO/CIO help

Depends on the size of the writes / reads .. CIO is only really good with block sizes of 1MB and upwards ..

http://www-03.ibm.com/servers/aix/wh...b_perf_aix.pdf

Run filemon to see what is going on and what file/LV your bottleneck is and post some output ..

Spreading the LV over more spindles is going probably going to be the quick fix .. unless you have contention on the same file / inode .. (you can use splat to analyse this also) - and sync_release_ilock may also be an option.

http://publib.boulder.ibm.com/infoce...mds5/splat.htm

you can tune ioo if you know what types of writes / reads you are doing i.e. sequential reads and sequential write and random writes can be tuned a little (random reads cannot)

Rgds
Mark Taylor

[Mark Taylor]

>> The data is temporary files for Sonic ESB/MQ Application

have you thought of using a ramdisk if its temp data ?

[Ran]

Hi Mark,

I'm going to try putting the filesystem on part of the SAN we have. Failing this I might go for your suggestion about the ram disk.

I've tried doing some tuning with some of the parameters but it does not make much of a difference. I think that's all the performance I'm going to get out of the one drive.

Spreading the load over several spindles sounds the way to go, I think this should give us more tps.

Many Thanks

Ran.