* MD and rotational attribute
@ 2012-02-20 12:20 Karel Zak
[not found] ` <20120227104230.125cb9e2@notabene.brown>
0 siblings, 1 reply; 3+ messages in thread
From: Karel Zak @ 2012-02-20 12:20 UTC (permalink / raw)
To: Neil Brown; +Cc: linux-kernel, linux-raid
Hi Neil,
I guess that something is wrong with MD. If you create a RAID on ssd
(or scsi_debug in my example) than MD device is reported as rotational.
Simple example:
modprobe scsi_debug dev_size_mb=500
fdisk /dev/sdb
...
mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sdb{1,2}
# cat /sys/block/sdb/queue/rotational
0
# cat /sys/block/md0/queue/rotational
1
It seems like a bug.
Karel
--
Karel Zak <kzak@redhat.com>
http://karelzak.blogspot.com
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: MD and rotational attribute
[not found] ` <20120227104230.125cb9e2@notabene.brown>
@ 2012-02-27 0:18 ` Martin K. Petersen
2012-02-27 0:40 ` NeilBrown
0 siblings, 1 reply; 3+ messages in thread
From: Martin K. Petersen @ 2012-02-27 0:18 UTC (permalink / raw)
To: NeilBrown; +Cc: Karel Zak, linux-kernel, linux-raid, Martin K.Petersen
>>>>> "Neil" == NeilBrown <neilb@suse.de> writes:
Neil,
Neil> (I would say that the name 'rotational' is a bug - the issues here
Neil> is really whether seek is fast or slow is it not??... but no
Neil> matter).
Both the ATA and SCSI specs use the term 'rotational' which I guess is
how we ended up with that name.
Neil> What do you think Martin? Should QUEUE_FLAG_NONROT move to
Neil> queue_limits much like QUEUE_FLAG_CLUSTER did?
Absolutely. I posted some patches converting both the nonrot and
discard/secure discard queue flags a while back but they didn't go
in. I'll freshen up the kit and resend...
--
Martin K. Petersen Oracle Linux Engineering
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: MD and rotational attribute
2012-02-27 0:18 ` Martin K. Petersen
@ 2012-02-27 0:40 ` NeilBrown
0 siblings, 0 replies; 3+ messages in thread
From: NeilBrown @ 2012-02-27 0:40 UTC (permalink / raw)
To: Martin K. Petersen; +Cc: Karel Zak, linux-kernel, linux-raid
[-- Attachment #1: Type: text/plain, Size: 792 bytes --]
On Sun, 26 Feb 2012 19:18:12 -0500 "Martin K. Petersen"
<martin.petersen@oracle.com> wrote:
> >>>>> "Neil" == NeilBrown <neilb@suse.de> writes:
>
> Neil,
>
> Neil> (I would say that the name 'rotational' is a bug - the issues here
> Neil> is really whether seek is fast or slow is it not??... but no
> Neil> matter).
>
> Both the ATA and SCSI specs use the term 'rotational' which I guess is
> how we ended up with that name.
>
>
> Neil> What do you think Martin? Should QUEUE_FLAG_NONROT move to
> Neil> queue_limits much like QUEUE_FLAG_CLUSTER did?
>
> Absolutely. I posted some patches converting both the nonrot and
> discard/secure discard queue flags a while back but they didn't go
> in. I'll freshen up the kit and resend...
>
Thanks!
NeilBrown
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 828 bytes --]
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2012-02-27 0:41 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2012-02-20 12:20 MD and rotational attribute Karel Zak
[not found] ` <20120227104230.125cb9e2@notabene.brown>
2012-02-27 0:18 ` Martin K. Petersen
2012-02-27 0:40 ` NeilBrown
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).