Originally posted by: SystemAdmin

I've recently installed AIX 5.2 on an IBM JS20 Blade Server. I'm running into very poor performance writing to the local disk. To some extent, I expect that, as the drive in the JS20 is a 5400 RPM laptop drive. Even with that in mind, it seems like I may have something that needs tuning. Sustained file writes (dd from /dev/zero) are clocking in at about 7.2Mbytes/sec. Things that involve lots of small file reads/writes are pretty much unusable.

I've gone into smit and set both the AIO (posix and legacy) to "available" with a fairly large number of servers and rebooted. That doesn't seem to have helped. I'm wondering if anyone is aware of any cache options, or other tunables that I may be missing which have a significant impact on JFS performance, especially for lots of small file I/O.

Currently a "make check" in the Bison source tree, which takes several minutes on linux is failing to reach the halfway mark when run overnight on the JS20.

Thanks in advance.

-Charles
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Originally posted by: IBMFORUMS

how many CPU, MEM, Paging space ....
if print output of topas commad.
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Originally posted by: MarkTaylor

You need to grab some perf metrics .. you have not said how your jfs2 filesystem is set up lv/pvs etc .. or what else is going on at the same time as your dd test .. paste some "filemon" and "vmstat 1 20" output .. if you dont know how to run filemon then download the perfpmr package and run the filemon.sh script which will do it all for you. Have you tried dd'ing to another disk on the system and its giving better performance ? what is you expectation for disk performance based on ?

Rgds
Mark Taylor
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