From: Jens Axboe <jens.axboe@oracle.com>
To: "Alan D. Brunelle" <Alan.Brunelle@hp.com>
Cc: Dmitri Monakhov <dmonakhov@openvz.org>, linux-fsdevel@vger.kernel.org
Subject: Re: write is faster whan seek?
Date: Wed, 11 Jun 2008 13:49:54 +0200 [thread overview]
Message-ID: <20080611114950.GW20851@kernel.dk> (raw)
In-Reply-To: <484FB92D.4090808@hp.com>
On Wed, Jun 11 2008, Alan D. Brunelle wrote:
> Dmitri Monakhov wrote:
>
> Could it be that in the first case you will have merges, thus creating
> fewer/larger I/O requests? Running iostat -x during the two runs, and
> watching the output is a good first place to start.
I think it's mostly down to whether a specific drive is good at doing
124kb writes + 4k seek (and repeat) compared to regular streaming
writes. The tested disk was SATA with write back caching, there should
be no real command overhead gain in those size ranges.
--
Jens Axboe
next prev parent reply other threads:[~2008-06-11 11:49 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-06-11 7:20 write is faster whan seek? Dmitri Monakhov
2008-06-11 7:48 ` Jens Axboe
2008-06-11 8:11 ` Dmitri Monakhov
2008-06-11 8:26 ` Jens Axboe
2008-06-11 9:28 ` Dmitri Monakhov
2008-06-11 9:38 ` Jens Axboe
2008-06-11 11:38 ` Alan D. Brunelle
2008-06-11 11:49 ` Jens Axboe [this message]
2008-06-11 11:52 ` Alan D. Brunelle
2008-06-11 11:55 ` Jens Axboe
2008-06-16 12:14 ` Dmitri Monakhov
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