From: Dave Chinner <david@fromorbit.com>
To: Ivan Pantovic <gyro.ivan@gmail.com>
Cc: linux-kernel@vger.kernel.org,
Speedy Milan <speedy.milan@gmail.com>,
xfs@oss.sgi.com
Subject: Re: rm -f * on large files very slow on XFS + MD RAID 6 volume of 15x 4TB of HDDs (52TB)
Date: Wed, 23 Apr 2014 18:25:38 +1000 [thread overview]
Message-ID: <20140423082538.GR18672@dastard> (raw)
In-Reply-To: <53576A7D.9020303@gmail.com>
On Wed, Apr 23, 2014 at 09:23:41AM +0200, Ivan Pantovic wrote:
>
> >[root@drive-b ~]# xfs_db -r /dev/md0
> >xfs_db> frag
> >actual 11157932, ideal 11015175, fragmentation factor 1.28%
> >xfs_db>
>
> this is current level of fragmentation ... is it bad?
http://xfs.org/index.php/XFS_FAQ#Q:_The_xfs_db_.22frag.22_command_says_I.27m_over_50.25._Is_that_bad.3F
> some say over 1% is candidate for defrag? ...
Some say that over 70% is usually not a problem:
http://www.mythtv.org/wiki/XFS_Filesystem#Defragmenting_XFS_Partitions
i.e. the level that becomes are problem is highly workload specific.
So, you can't read *anything* in that number without know exactly
what is in your filesystem, how the application(s) interact with it
and so on.
Besides, I was asking specifically about the files you removed, not
the files that remain in the filesystem. Given that you have 11
million inodes in the filesystem, you probably removed the only
significantly large files in the filesystem....
So, the files your removed are now free space, so free space
fragmentation is what we need to look at. i.e. use the freesp
command to dump the histogram and summary of the free space...
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:[~2014-04-23 8:26 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CAHuzUScfp19c_th_pfsZs05+yDz34MuEH-P1f+FF1dcivfH=5Q@mail.gmail.com>
2014-04-23 2:18 ` rm -f * on large files very slow on XFS + MD RAID 6 volume of 15x 4TB of HDDs (52TB) Dave Chinner
2014-04-23 7:23 ` Ivan Pantovic
2014-04-23 8:25 ` Dave Chinner [this message]
2014-04-23 9:21 ` Ivan Pantovic
2014-04-23 22:12 ` 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=20140423082538.GR18672@dastard \
--to=david@fromorbit.com \
--cc=gyro.ivan@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=speedy.milan@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;
as well as URLs for NNTP newsgroup(s).