From: Richard Scobie <richard@sauce.co.nz>
To: thomas62186218@aol.com
Cc: linux-raid@vger.kernel.org
Subject: Re: Software RAID 6 initial sync very slow
Date: Mon, 02 Jun 2008 08:37:46 +1200 [thread overview]
Message-ID: <4843089A.7040909@sauce.co.nz> (raw)
In-Reply-To: <8CA91F18992AC9E-1724-EAF@webmail-ne13.sysops.aol.com>
thomas62186218@aol.com wrote:
> My first test was to create a RAID 6 md device, 128K chunk, with all 12
> drives. The sync is currently underway at a very slow 30MB/sec, with
> mdadm estimating this as a 9hr process. With an Adaptec 5805 RAID card
> tested, I performed the RAID 6 initial sync with the same 12 drives in
> just under 5 hours. Meanwhile, our total CPU usage during mdadm syncing
> is at 5%, so there's plenty of CPU not being used.
I have a very similar system, except single quad core and 16 x 750GB
It syncs (md RAID6) in 3:40min which is roughly proportional to the time
you see with your hardware RAID sync up, so you should be able to match
it with md RAID.
I cannot remember whether stripe_cache_size affected the sync time -
currently I have this set to 16384.
Regards,
Richard
next prev parent reply other threads:[~2008-06-01 20:37 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-06-01 11:26 Software RAID 6 initial sync very slow thomas62186218
2008-06-01 20:37 ` Richard Scobie [this message]
2008-06-02 12:35 ` Bill Davidsen
2008-06-02 19:18 ` thomas62186218
2008-06-03 1:08 ` Richard Scobie
2008-06-03 5:11 ` Neil Brown
2008-06-03 19:47 ` Bill Davidsen
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