identify i/o process

[Fraser Campbell]

On Tuesday 01 May 2007 16:29:29 Jose wrote:

> I am having problem with a server, ti slows down and the disk i/o goes
> to 100%, I couldn't figure out how to run ps to allow me to see which
> process is the one giving me the trouble, does anybody know how to
> identify process doing lots of disk i/o?

There is the manual way ...

iostat can show you which particular devices are getting most io (so can sar 
over longer periods).  You could then use lsof to see what open files are on 
that device, ps looking for processes waiting for I/O (state D).

There are some automated ways ...

If your distribution supports systemtap that should be the best way though the 
learning curve isn't short.

IBM has a good presentation on systemtap that includes specific examples of 
how to find "Top IO Users by Process ID" and "Top IO Users by User ID" ... 
http://sourceware.org/systemtap/wiki/HomePage?action=AttachFile&do=get&target=LWESFO06.pdf

-- 
Fraser Campbell <fraser-Txk5XLRqZ6CsTnJN9+BGXg at public.gmane.org>
Georgetown, Ontario, Canada
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