From: Mike Fedyk <mfedyk@matchmail.com>
To: Neil Brown <neilb@cse.unsw.edu.au>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Raid5 resync slow with one linear array
Date: Thu, 4 Apr 2002 14:56:43 -0800 [thread overview]
Message-ID: <20020404225643.GG961@matchmail.com> (raw)
In-Reply-To: <20020402022822.GA961@matchmail.com> <15531.53380.136055.226784@notabene.cse.unsw.edu.au>
On Thu, Apr 04, 2002 at 02:03:16PM +1000, Neil Brown wrote:
> On Monday April 1, mfedyk@matchmail.com wrote:
> > Hi,
> >
> > I just setup a 4 (5 really) drive raid5 array.
> >
> > It is syncing up right now and nothing else is running on the system.
> >
> > I have three 18GB SCA scsi drives and 2x9GB linear array in a four "drive"
> > raid5 array.
> >
> > Unfortunately, it is syncing up quite slowly. Only about 2MB/sec on a
> > 40MB/sec array. The system is idle.
> >
> > 2.4.19-pre4-ac3
> >
> > Is there something about this config that says "Don't do that!"? I've
> > heard about RAID10, but not Linear+RAID5...
>
> echo 10000 > /proc/sys/dev/raid/speed_limit_min
>
> md tries to monitor the activity on the component devices and limits
> rebuild activity when there appears to be other activity.
> It measures "other activity" as "blocks added to kstat.dk_drive_?blk",
> minus "block due to resync activity".
>
> When a component device is an md array, nothing gets recorded
> in kstat, but lots is recorded as resync activity, so this "other
> activity" appears as a negative number which, due to storage in an
> unsigned long, appears rather large.
>
> NeilBrown
Yeah, thought it was something like that. Thanks for the explanation. I
didn't see your message until I sent the other one.
Mike
prev parent reply other threads:[~2002-04-04 22:55 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-04-02 2:28 Raid5 resync slow with one linear array Mike Fedyk
[not found] ` <Pine.LNX.4.44.0204020630140.1152-100000@pc24.sr.bham.ac.uk>
2002-04-03 0:52 ` Mike Fedyk
[not found] ` <Pine.LNX.4.44.0204042255040.8182-100000@pc24.sr.bham.ac.uk>
2002-04-04 22:04 ` Mike Fedyk
2002-04-04 4:03 ` Neil Brown
2002-04-04 22:56 ` Mike Fedyk [this message]
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