SUMMARY: which process is swamping my root disk ?

From: Guy Dallaire (
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:


Have you tried using proctool from ? 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...


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.


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.


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.


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

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

This archive was generated by hypermail 2.1.2 : Fri Sep 28 2001 - 23:14:04 CDT