From: Michael Monnerie <michael.monnerie@is.it-management.at>
To: xfs@oss.sgi.com
Cc: Christoph Hellwig <hch@infradead.org>,
Wu Fengguang <fengguang.wu@intel.com>
Subject: Re: [PATCH] xfs: improve sync behaviour in face of aggressive dirtying
Date: Tue, 21 Jun 2011 09:21:46 +0200 [thread overview]
Message-ID: <201106210921.48657@zmi.at> (raw)
In-Reply-To: <20110621003343.GJ32466@dastard>
[-- Attachment #1.1: Type: Text/Plain, Size: 1176 bytes --]
On Dienstag, 21. Juni 2011 Dave Chinner wrote:
> > The minor one is that we always flush all work items and not just
> > those on the filesystem to be flushed. This might become an issue
> > for lager systems, or when we apply a similar scheme to fsync,
> > which has the same underlying issue.
>
> For sync, I don't think it matters if we flush a few extra IO
> completions on a busy system.
Couldn't that be bad on a system with mixed fast/slow storage (say 15k
SAS and 7.2k SATA), where on the busy fast SAS lots of syncs occur and
lead to extra I/O on the SATA disks? Especially if there are 16 SAS
disks in an array with RAID-0 against 4 SATA disks in RAID-6, to say the
worst. If the SATAs are already heavy used (say >=50%), those extra
writes could bring them to their knees.
I'm not sure how often syncs occur though, maybe that's why Dave says it
shouldn't matter? AFAIK, databases generate heavy syncs though.
--
mit freundlichen Grüssen,
Michael Monnerie, Ing. BSc
it-management Internet Services: Protéger
http://proteger.at [gesprochen: Prot-e-schee]
Tel: +43 660 / 415 6531
// Haus zu verkaufen: http://zmi.at/langegg/
[-- Attachment #1.2: This is a digitally signed message part. --]
[-- Type: application/pgp-signature, Size: 198 bytes --]
[-- Attachment #2: Type: text/plain, Size: 121 bytes --]
_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs
next prev parent reply other threads:[~2011-06-21 7:21 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-17 13:14 [PATCH] xfs: improve sync behaviour in face of aggressive dirtying Christoph Hellwig
2011-06-20 8:18 ` Christoph Hellwig
2011-06-21 0:33 ` Dave Chinner
2011-06-21 7:21 ` Michael Monnerie [this message]
2011-06-22 0:19 ` Dave Chinner
2011-06-21 9:29 ` Christoph Hellwig
2011-06-22 1:09 ` Dave Chinner
2011-06-22 6:51 ` Christoph Hellwig
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=201106210921.48657@zmi.at \
--to=michael.monnerie@is.it-management.at \
--cc=fengguang.wu@intel.com \
--cc=hch@infradead.org \
--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