From: Jens Axboe <axboe@kernel.dk>
To: Mike Snitzer <snitzer@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>,
linux kernel mailing list <linux-kernel@vger.kernel.org>,
martin.petersen@oracle.com
Subject: Re: [RFC PATCH] block: Change default IO scheduler to deadline except SATA
Date: Tue, 10 Apr 2012 20:36:27 +0200 [thread overview]
Message-ID: <4F847DAB.5030707@kernel.dk> (raw)
In-Reply-To: <CAMM=eLf5qi_PL8vFh_b5V_nq_mxg0CN0asE8E9XYJn48J4mdPA@mail.gmail.com>
On 2012-04-10 18:13, Mike Snitzer wrote:
> That said, we can have a _very_ good hint that a SCSI device is a raid array if:
>
> 1) optimal_io_size is not zero, minimum_io_size is not equal to
> optimal_io_size, and optimal_io_size is a multiple of minimum_io_size
>
> 2) WCE=0 (higher-end arrays with a writeback cache)
Any other device than a basic SATA disk will have WCE=0. So I don't
think that gives you a very good hint of the nature of it,
unfortunately.
--
Jens Axboe
next prev parent reply other threads:[~2012-04-10 18:36 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-10 13:37 [RFC PATCH] block: Change default IO scheduler to deadline except SATA Vivek Goyal
2012-04-10 13:56 ` Jens Axboe
2012-04-10 14:21 ` Vivek Goyal
2012-04-10 15:10 ` Vivek Goyal
2012-04-10 16:13 ` Mike Snitzer
2012-04-10 17:28 ` Vivek Goyal
2012-04-10 17:40 ` Mike Snitzer
2012-04-10 18:36 ` Jens Axboe [this message]
2012-04-11 16:25 ` Martin K. Petersen
2012-04-10 18:41 ` Jens Axboe
2012-04-10 18:53 ` Vivek Goyal
2012-04-10 18:56 ` Jens Axboe
2012-04-10 19:11 ` Vivek Goyal
2012-04-10 19:19 ` Jens Axboe
2012-04-10 19:43 ` Mike Snitzer
2012-04-10 19:55 ` Jens Axboe
2012-04-10 20:12 ` Mike Snitzer
-- strict thread matches above, loose matches on Subject: below --
2012-04-10 17:44 Xose Vazquez Perez
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