From: NeilBrown <neilb@suse.de>
To: Linux Raid Study <linuxraid.study@gmail.com>
Cc: Robin Hill <robin@robinhill.me.uk>, linux-raid@vger.kernel.org
Subject: Re: iostat with raid device...
Date: Tue, 12 Apr 2011 12:51:41 +1000 [thread overview]
Message-ID: <20110412125141.679baaf0@notabene.brown> (raw)
In-Reply-To: <BANLkTinFxHPuCgxERGc88W2KmZkzU_GF9Q@mail.gmail.com>
On Mon, 11 Apr 2011 18:57:34 -0700 Linux Raid Study
<linuxraid.study@gmail.com> wrote:
> If I use --assume-clean in mdadm, I see performance is 10-15% lower as
> compared to the case wherein this option is not specified. When I run
> without --assume_clean, I wait until mdadm prints "recovery_done" and
> then run IO benchmarks...
>
> Is perf drop expected?
No. And I cannot explain it.... unless the array is so tiny that it all fits
in the stripe cache (typically about 1Meg).
There really should be no difference.
NeilBrown
next prev parent reply other threads:[~2011-04-12 2:51 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-08 19:55 iostat with raid device Linux Raid Study
2011-04-08 22:05 ` Roberto Spadim
2011-04-08 22:10 ` Linux Raid Study
2011-04-08 23:46 ` NeilBrown
2011-04-09 0:40 ` Linux Raid Study
2011-04-09 8:50 ` Robin Hill
2011-04-11 8:32 ` Linux Raid Study
2011-04-11 9:25 ` Robin Hill
2011-04-11 9:36 ` Linux Raid Study
2011-04-11 9:53 ` Robin Hill
2011-04-11 10:18 ` NeilBrown
2011-04-12 1:57 ` Linux Raid Study
2011-04-12 2:51 ` NeilBrown [this message]
2011-04-12 19:36 ` Linux Raid Study
2011-04-13 18:21 ` Linux Raid Study
2011-04-13 21:00 ` NeilBrown
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