From: Lutz Vieweg <lvml@5t9.de>
To: linux-raid@vger.kernel.org
Subject: Re: Using the new bad-block-log in md for Linux 3.1
Date: Wed, 27 Jul 2011 15:23:14 +0200 [thread overview]
Message-ID: <j0p3g2$ua5$1@dough.gmane.org> (raw)
In-Reply-To: <j0p2g2$nmp$1@dough.gmane.org>
On 07/27/2011 03:06 PM, Lutz Vieweg wrote:
>> I don't think mdadm knows whether its constituent devices are SSDs.
>
> In block/cfq-iosched.c I see a test that looks like this:
>> if (blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag)
>> return;
I just verified that indeed, /sys/block/sd*/queue/rotational contains
0 for SSDs and 1 for magnetic disks.
One catch, though, seems to be that this attribute seems not to be
propagated through additional block device layers, so e.g.
a loop-device based on a SSD is, strangely, tagged as being "rotational",
as is a device-mapper based on the SSD.
So you can detect SSDs if given as underlying devices directly, only.
Regards,
Lutz Vieweg
next prev parent reply other threads:[~2011-07-27 13:23 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-27 4:16 Using the new bad-block-log in md for Linux 3.1 NeilBrown
2011-07-27 6:21 ` keld
2011-07-27 6:49 ` NeilBrown
2011-07-27 8:17 ` keld
2011-07-27 10:22 ` Mikael Abrahamsson
2011-07-27 12:30 ` Lutz Vieweg
2011-07-27 12:44 ` John Robinson
2011-07-27 13:06 ` Lutz Vieweg
2011-07-27 13:23 ` Lutz Vieweg [this message]
2011-07-27 20:55 ` NeilBrown
2011-07-28 9:25 ` Lutz Vieweg
2011-07-28 9:55 ` John Robinson
2011-07-28 12:53 ` Michal Soltys
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