From: Andreas Dilger <adilger@turbolabs.com>
To: David Hajek <david@atrey.karlin.mff.cuni.cz>
Cc: linux-kernel@vger.kernel.org
Subject: Re: high cpu load with sw raid1
Date: Fri, 21 Sep 2001 02:09:38 -0600 [thread overview]
Message-ID: <20010921020938.I14526@turbolinux.com> (raw)
In-Reply-To: <20010920102616.A2753@pida.ulita.cz> <20010920124020.D14526@turbolinux.com> <20010921090720.A12970@pida.ulita.cz>
In-Reply-To: <20010921090720.A12970@pida.ulita.cz>
On Sep 21, 2001 09:07 +0200, David Hajek wrote:
> On Thu, Sep 20, 2001, Andreas Dilger wrote:
> > On Sep 20, 2001 10:26 +0200, David Hajek wrote:
> > > I have linux box with 70GB SW Raid1. This box runs for half
> > > a year without problems but now I meet the high cpu load
> > > problems. I suspect that it can be caused by not enough
> > > free disk space on this md device. I see following:
> > >
> > > 1 GB free - load > 5
> > > 5 GB free - load < 1
> >
> > What filesystem are you using? If it is reiserfs, and you have < 10%
> > of the disk free, it is very unhappy. A patch to fix this is available.
>
> I'm using ext2. I suspect high ext2 fragmentation, because when
> there are 'only' 1GB free the disk is _really_ busy. I doubt
> that it takes lot of time to find free blocks.
OK, I just re-read your initial posting, and see you have a 70GB RAID,
so 1GB free is about 1.4% free, which makes for bad performance no
matter what filesystem you have. In general, ext2 will have this 1%
free space spread evenly across all of the disk, so while 1GB is still
a lot of space, it is still a nearly full filesystem.
Cheers, Andreas
--
Andreas Dilger \ "If a man ate a pound of pasta and a pound of antipasto,
\ would they cancel out, leaving him still hungry?"
http://www-mddsp.enel.ucalgary.ca/People/adilger/ -- Dogbert
prev parent reply other threads:[~2001-09-21 8:10 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-09-20 8:26 high cpu load with sw raid1 David Hajek
2001-09-20 9:10 ` Jakob Østergaard
2001-09-20 9:23 ` David Hajek
2001-09-20 10:38 ` Jakob Østergaard
2001-09-20 18:40 ` Andreas Dilger
2001-09-21 7:07 ` David Hajek
2001-09-21 8:09 ` Andreas Dilger [this message]
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