From: NeilBrown <neilb@suse.com>
To: Marc Smith <marc.smith@mcc.edu>, linux-raid@vger.kernel.org
Subject: Re: RAID10 Write Performance
Date: Wed, 23 Dec 2015 13:20:49 +1100 [thread overview]
Message-ID: <87wps529dq.fsf@notabene.neil.brown.name> (raw)
In-Reply-To: <CAHkw+LeVkGo8cOGMzQbq7sGtw5K9bc3CMOvurL0kjDf0ZWTfsA@mail.gmail.com>
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On Wed, Dec 23 2015, Marc Smith wrote:
> Solved... appears it was the write-intent bitmap that caused the
> performance issues. I discovered if I left the test running longer
> than 60 seconds, the performance would eventually climb to where I'd
> expect it. I ran 'mdadm --grow --bitmap=none /dev/md0' and now random
> write performance is high/good/stable right off the bat.
Keeping a write-intent bitmap really is a good idea.
Using a larger bitmap chunk size can reduce the performance penalty and
preserve much of the value. It is easy enough to experiment with
different sizes.
NeilBrown
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next prev parent reply other threads:[~2015-12-23 2:20 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-18 18:43 RAID10 Write Performance Marc Smith
2015-12-22 19:36 ` Marc Smith
2015-12-23 2:20 ` NeilBrown [this message]
2015-12-23 13:59 ` Marc Smith
2015-12-23 22:58 ` NeilBrown
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