Date: Sat, 20 Feb 2010 23:56:24 +0300 From: Boris Samorodov <bsam@ipt.ru> To: Dan Nelson <dnelson@allantgroup.com> Cc: freebsd-questions@freebsd.org Subject: Re: strange disk activity Message-ID: <88797383@ipt.ru> In-Reply-To: <20100220202614.GG70798@dan.emsphone.com> (Dan Nelson's message of "Sat, 20 Feb 2010 14:26:15 -0600") References: <97752307@ipt.ru> <20100220202614.GG70798@dan.emsphone.com>
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On Sat, 20 Feb 2010 14:26:15 -0600 Dan Nelson wrote:
> In the last episode (Feb 20), Boris Samorodov said:
> > Hello List,
> >
> > I've got a very strange disk activity:
> > -----
> > % iostat -xw60 da0
> > extended device statistics
> > device r/s w/s kr/s kw/s wait svc_t b
> > da0 43.2 204.4 971.9 10917.2 0 30.7 30
> > extended device statistics
> > device r/s w/s kr/s kw/s wait svc_t b
> > da0 5.1 274.6 72.7 15206.2 0 50.4 27
> >
> > If I'm not mistaken it's approx. 15Mb/sec. Which means more than 1000 Tb a
> > day!
> >
> > How can I find which program is trashing the disk? The system is
> > FreeBSD-7.0 with 15 jails. Thanks for your help.
> Something like this would be a good start:
> dtrace -n 'syscall::write:entry { @dist[pid,execname] = sum(arg2); }'
> Let it run a few seconds, then hit ^C, and it will print the total bytes
> written by each process during that period. You may also have to trace
> writev and pwrite, since FreeBSD's dtrace doesn't include the sysinfo
> provider that would let you count them all at once.
> Data written to swap or mmap'ped files won't register here, but most heavy
> writes aren't done with mmap.
Thanks, Dan! Dtrace is really a way to go.
Unfortunately dtrace is not available at 7.0. That means that
the system should be updated to 7-STABLE.
Are there other possibilities meanwhile?
--
WBR, Boris Samorodov (bsam)
Research Engineer, http://www.ipt.ru Telephone & Internet SP
FreeBSD Committer, http://www.FreeBSD.org The Power To Serve
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