From: Richard Scobie <richard@sauce.co.nz>
To: linux-raid@vger.kernel.org
Subject: Re: raid5 grow reshaping speed is unchangeable
Date: Sat, 29 Dec 2007 17:38:12 +1300 [thread overview]
Message-ID: <4775CF34.7030400@sauce.co.nz> (raw)
In-Reply-To: <380-2200712528192139967@mochamail.com>
Cody Yellan wrote:
> You are right, Richard. RHEL5 had a stripe_cache_size of 256 when
> the reshape began. I increased it to 1024 and the reshape speed
> doubled to 4500K/s. I did not see any increase in memory usage. I
> tried 2048 and then 4096 but saw no difference in speed.
Sorry, I did not make myself clear.
Back when I was seeing the slow resync speeds, it was due to larger than
default stripe_cache_size - I had increased to 16384.
When this was reduced back to the default, which I suspect is 256,
speeds were back up to more normal levels - much faster than the 4.5MB/s
you are seeing.
At some point, this issue was fixed and currently on 2.6.22, with a
stripe_cache_size of 16384 and a 4 x 500GB SATA II md RAID 5, resync
speed is 162MB/s.
Perhaps somthing different occurs on a reshape, (which I have only now
realised you were doing).
Regards,
Richard
next prev parent reply other threads:[~2007-12-29 4:38 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-28 19:21 raid5 grow reshaping speed is unchangeable Cody Yellan
2007-12-29 4:38 ` Richard Scobie [this message]
-- strict thread matches above, loose matches on Subject: below --
2007-12-29 0:52 Cody Yellan
2007-12-27 7:46 Cody Yellan
2007-12-28 0:57 ` Bill Davidsen
2007-12-27 5:22 Cody Yellan
2007-12-27 22:10 ` Nagilum
2007-12-28 0:53 ` Bill Davidsen
2007-12-28 3:13 ` Richard Scobie
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