From: Dave Chinner <david@fromorbit.com>
To: Stefan Priebe <s.priebe@profihost.ag>
Cc: dchinner@redhat.com, Christoph Hellwig <hch@lst.de>,
Ronnie Sahlberg <ronniesahlberg@gmail.com>,
"xfs@oss.sgi.com" <xfs@oss.sgi.com>
Subject: Re: aborted SCSI commands while discarding/unmapping via mkfs.xfs
Date: Wed, 15 Aug 2012 07:35:35 +1000 [thread overview]
Message-ID: <20120814213535.GK2877@dastard> (raw)
In-Reply-To: <502AB82D.9090408@profihost.ag>
On Tue, Aug 14, 2012 at 10:42:21PM +0200, Stefan Priebe wrote:
> Hello list,
>
> i'm testing KVM with qemu, libiscsi, virtio-scsi-pci and
> scsi-general on top of a nexenta storage solution. While doing
> mkfs.xfs on an already used LUN / block device i discovered that the
> unmapping / discard commands mkfs.xfs sends take a long time which
> results in a lot of aborted scsi commands.
Sounds like a problem with your storage being really slow at
discards.
> Would it make sense to let mkfs.xfs send these unmapping commands in
> small portations (f.e. 100MB)
No, because the underlying implementation (blkdev_issue_discard())
already breaks the discard request up into the granularity that is
supported by the underlying storage.....
> or is there another problem in the
> patch to the block device? Any suggestions or ideas?
.... which, of course, had bugs in it so is a muchmore likely cause
of your problems.
That said,the discard granularity is derived from information the
storage supplies the kernel in it's SCSI mode page, so if the
discard granularity is too large, that's a storage problem, not a
linux problem at all, let alone a mkfs.xfs problem.
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs
next prev parent reply other threads:[~2012-08-14 21:35 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-14 20:42 aborted SCSI commands while discarding/unmapping via mkfs.xfs Stefan Priebe
2012-08-14 21:35 ` Dave Chinner [this message]
2012-08-14 21:51 ` ronnie sahlberg
2012-08-15 7:32 ` Dave Chinner
2012-08-15 6:31 ` Stefan Priebe - Profihost AG
2012-08-15 9:13 ` Michael Monnerie
2012-08-15 9:14 ` Stefan Priebe - Profihost AG
2012-08-15 9:22 ` Stefan Ring
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20120814213535.GK2877@dastard \
--to=david@fromorbit.com \
--cc=dchinner@redhat.com \
--cc=hch@lst.de \
--cc=ronniesahlberg@gmail.com \
--cc=s.priebe@profihost.ag \
--cc=xfs@oss.sgi.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox