From: Al Boldi <a1426z@gawab.com>
To: Willy Tarreau <willy@w.ods.org>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Eradic disk access during reads
Date: Sun, 18 Sep 2005 07:16:46 +0300 [thread overview]
Message-ID: <200509180716.46978.a1426z@gawab.com> (raw)
In-Reply-To: <20050917184643.GA1313@alpha.home.local>
Willy Tarreau wrote:
> On Sat, Sep 17, 2005 at 01:32:53PM +0300, Al Boldi wrote:
> > Willy Tarreau wrote:
> > > On Sat, Sep 17, 2005 at 07:26:11AM +0300, Al Boldi wrote:
> > > > Monitoring disk access using gkrellm, I noticed that a command like
> > > >
> > > > cat /dev/hda > /dev/null
> > > >
> > > > shows eradic disk reads ranging from 0 to 80MB/s on an otherwise
> > > > idle system.
New synonym: eradic=erratic :)
> Denis' tool seems clearly more suited to analyse your problem.
The problem seems to be a multi-access collision in the queue, which forces a
~50% reduction of thruput, which recovers with another multi-access
collision. Maybe?!
--
Al
next prev parent reply other threads:[~2005-09-18 4:17 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-09-17 4:26 Al Boldi
2005-09-17 5:50 ` Willy Tarreau
2005-09-17 10:32 ` Al Boldi
2005-09-17 10:44 ` Denis Vlasenko
2005-09-17 16:38 ` Al Boldi
2005-09-18 11:00 ` Denis Vlasenko
2005-09-18 13:40 ` Al Boldi
2005-09-18 16:02 ` Denis Vlasenko
2005-09-18 16:34 ` Willy Tarreau
2005-09-18 18:08 ` Al Boldi
2005-09-17 18:46 ` Willy Tarreau
2005-09-18 4:16 ` Al Boldi [this message]
2005-09-18 5:23 ` Willy Tarreau
2005-09-18 6:54 ` Al Boldi
2005-09-18 10:40 ` Denis Vlasenko
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