From: Florian Weimer <fweimer@bfk.de>
To: xfs@oss.sgi.com
Subject: XFS on 2.6.26: reading the first 4K of a large file takes ages
Date: Wed, 19 May 2010 11:33:27 +0000 [thread overview]
Message-ID: <8239xojfco.fsf@mid.bfk.de> (raw)
We've got a couple of rather large files, and with a cold cache,
reading the first 4K bytes of the file (e.g., just running
"head --bytes 4096" on it) takes ages, up to several minutes,
sometimes triggering the hang check timer.
I wonder if XFS reads the whole extent information into RAM when the
file is opened. Is this the case, at least on 2.6.26? Has this
changed in later versions, perhaps?
The files in question are heavily fragmented (they have been created
with holes first, and the holes have been filled in subsequently).
I'll try to run xfs_fsr on those files, but it's going to be
tough. 8-/
--
Florian Weimer <fweimer@bfk.de>
BFK edv-consulting GmbH http://www.bfk.de/
Kriegsstraße 100 tel: +49-721-96201-1
D-76133 Karlsruhe fax: +49-721-96201-99
_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs
next reply other threads:[~2010-05-19 11:31 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-19 11:33 Florian Weimer [this message]
2010-05-19 11:48 ` XFS on 2.6.26: reading the first 4K of a large file takes ages Christoph Hellwig
2010-05-19 23:27 ` Dave Chinner
2010-05-20 12:11 ` Florian Weimer
2010-05-21 6:20 ` Stewart Smith
2010-05-21 6:43 ` Florian Weimer
2010-05-21 8:26 ` 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=8239xojfco.fsf@mid.bfk.de \
--to=fweimer@bfk.de \
--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