From: "Keld J�rn Simonsen" <keld@dkuug.dk>
To: sminded <daniel.zetterman@gmail.com>
Cc: linux-raid@vger.kernel.org
Subject: Re: Faster read performance DURING (?) resync on raid10
Date: Thu, 25 Sep 2008 20:40:40 +0200 [thread overview]
Message-ID: <20080925184040.GA8608@rap.rap.dk> (raw)
In-Reply-To: <19666016.post@talk.nabble.com>
On Thu, Sep 25, 2008 at 02:27:51AM -0700, sminded wrote:
>
> I have done some automated scripted tests with bonnie++ over RAID10 and
> encryption, using different encryption cipher modes to evaluate the impact
> on I/O operations.
> The strange thing is that I can see a significant increase in read
> performance (about 20%) when running the tests DURING the raid resync phase
> directly after the raid creation as appose to running it after the resync,
> or after I create the array with --assume-clean (which skips initial
> resync).
>
> Have anyone noticed the same behaviour, and how can it be explained? Any
> ideas?
>
> Can someone else verify that they get the same result?
I noticed something similar, vastly enhanced performance just after
creation, but found out that some parameters needed to be changed,
setreadahead or some such.
What are the actual figures?
Best regards
Keld
next prev parent reply other threads:[~2008-09-25 18:40 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-25 9:27 Faster read performance DURING (?) resync on raid10 sminded
2008-09-25 18:40 ` Keld J�rn Simonsen [this message]
2008-09-26 4:18 ` Neil Brown
2008-09-26 23:19 ` Daniel Zetterman
2008-09-28 2:23 ` Keld J�rn Simonsen
2008-09-28 10:45 ` Daniel Zetterman
2008-09-28 11:06 ` Daniel Zetterman
2008-09-28 17:35 ` Keld Jørn Simonsen
2008-09-26 8:03 ` John Robinson
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