From: Stan Hoeppner <stan@hardwarefreak.com>
To: Ben Myers <bpm@sgi.com>
Cc: Jan Perci <jperci@gmail.com>, xfs@oss.sgi.com
Subject: Re: Help with XFS in VMs on VMFS
Date: Sat, 30 Mar 2013 14:12:36 -0500 [thread overview]
Message-ID: <51573924.2020304@hardwarefreak.com> (raw)
In-Reply-To: <20130329202735.GX22182@sgi.com>
On 3/29/2013 3:27 PM, Ben Myers wrote:
> Hi Jan,
>
> On Thu, Mar 28, 2013 at 11:30:01PM -0400, Jan Perci wrote:
>> Back to XFS, in this context, is there any benefit in tuning some
>> parameters to get better performance, or will it all just be overshadowed
>> by poor performance of the VMDKs that tuning isn't worthwhile?
>
> At least get your stripe unit and width correct.
> http://xfs.org/index.php/XFS_FAQ#Q:_How_to_calculate_the_correct_sunit.2Cswidth_values_for_optimal_performance
Is this really a good idea given that XFS sits atop a virtual disk which
consists of multiple concatenated 2TB sparse files sitting on the VMFS
filesystem, which, IIRC, has a 1MB sector size? Thus can one rely on
XFS being able to properly align to the physical RAID stripe, even if
the math is done 'properly' (if that's even possible here)?
In a complex stack like this I'd recommend defaults across the board.
Misalignment hurts performance far more than proper alignment increases
it. No alignment is agnostic, 4KB IOs only, so you neither gain nor lose.
> Beyond that I suggest you stick with the defaults unless you have a specific
> need. e.g. heavy usage of extended attributes might prompt you to use a larger
> inode size to keep them inline.
--
Stan
_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs
next prev parent reply other threads:[~2013-03-30 19:12 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-28 13:21 Help with XFS in VMs on VMFS Jan Perci
2013-03-28 14:59 ` Stefan Ring
2013-03-28 19:50 ` Stan Hoeppner
2013-03-28 21:45 ` Ralf Gross
2013-03-28 22:13 ` Emmanuel Florac
2013-03-29 14:23 ` Ralf Gross
2013-03-29 0:56 ` Stan Hoeppner
2013-03-29 3:30 ` Jan Perci
2013-03-29 20:27 ` Ben Myers
2013-03-30 19:12 ` Stan Hoeppner [this message]
2013-03-31 2:04 ` Dave Chinner
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=51573924.2020304@hardwarefreak.com \
--to=stan@hardwarefreak.com \
--cc=bpm@sgi.com \
--cc=jperci@gmail.com \
--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