SUMMARY: which process is swamping my root disk ?

From: Guy Dallaire (gdallair@criq.qc.ca)
Date: Tue Mar 14 2000 - 12:15:21 CST


Thanks to all the people who responded.

I have received many suggestions. I found out that proctool might be a good solution to my problem itf it ever resurfaces, because you can drill down in specific process and see their resource usages.

Here are the suggestions I received:

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Have you tried using proctool from http://www.sunfreeware.com ? This tool is of immense help to see what is really happening in the system. A must-have for all sys admins.

NOTE: Had to go to a mirror site to download...

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You can try using TOP, which lists processes by cpu utilization.
There may be an option to have it show you disk utilization, but
I'm not sure.

top might help - see who is up there in I/O wait. Unfortunately, until
I get PERFS (PERformance FS) done, there's little else to find an I/O
or disk hog.

NOTE: top was not really useful in this case.

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Maybe you want to write a script that does a "/usr/proc/bin/ptime <pid>" of all the process on the disk and see which process is spend
the most time in the sys.

NOTE: This sounded interesting, had not taught of this one.

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lsof is great for showing what's in use, but not how it's being used :)

If you have top, you may try just seeing which process(es) is sucking the
most CPU. That much I/O would leave it cpubound for a while, as well.

If you don't have top, you may try /usr/ucb/ps auxwwww ...that lists processes
by cpu usage. The first several prcoesses would be the most active.

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The "Red Porche" book (I think it's Sun performance and tuning, volume 2
by Adrian Cockcroft) has a detailed section on how to use the 'prex'
tool to analyze file system access on a per device level and a per
process level.

Most of Mr. Cockcroft's articles have appeared on sunworld before and
may be available there. I would do a search for 'prex' and see if you
can turn up the tutorial article.

The actual article was an analysis of why a particular disk was giving
very long service times at a regular interval according to iostat.

--------------------

Guy Dallaire
Centre de recherche industrielle du Québec
Ste-Foy, QC, Canada
Phone: (418) 659-1550 x 2612
e-mail: gdallair-nospam@criq.qc.ca

Note: remove "-nospam" from my e-mail



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