From: jim owens <owens6336@gmail.com>
To: David Newall <davidn@davidnewall.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>,
Jeff Garzik <jeff@garzik.org>,
linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org,
Akira Fujita <a-fujita@rs.jp.nec.com>
Subject: Re: defrag deployment status (was Re: [PATCH] ext4: allow defrag (EXT4_IOC_MOVE_EXT) in 32bit compat mode)
Date: Mon, 08 Mar 2010 11:22:15 -0500 [thread overview]
Message-ID: <4B952437.8020607@gmail.com> (raw)
In-Reply-To: <4B9518DA.8010201@davidnewall.com>
David Newall wrote:
> Christian Borntraeger wrote:
>> Some bigger things are missing in the e4defrag tool:
>> ...
>> - overall layout considerations (e.g. putting files close to its
>> directory or
>> use the atime to move often used files to the beginning of a disk etc.)
>
> Shouldn't oft-used files be placed closer to the middle? If you place
> them at the beginning of the file, it's only possible for the head-stack
> to be close to the file from the inner direction. Place them in the
> middle and it's possible for the head-stack to be close from the outer
> direction, too, which sounds like a doubling of probability. It seems
> that it's the least frequently used files that should be placed at one
> end of the disk or the other.
No. Your logic would be correct if rotating disks had
similar speed at all locations. Current disks are much
faster at the 0 end than at the middle or highest address.
It is not unusual to see 2x difference in transfer speed
so you always want the important stuff as low as possible.
jim
next prev parent reply other threads:[~2010-03-08 16:22 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-07 20:32 [PATCH] ext4: allow defrag (EXT4_IOC_MOVE_EXT) in 32bit compat mode Christian Borntraeger
2010-03-07 23:27 ` defrag deployment status (was Re: [PATCH] ext4: allow defrag (EXT4_IOC_MOVE_EXT) in 32bit compat mode) Jeff Garzik
2010-03-08 5:43 ` Eric Sandeen
2010-03-08 7:53 ` Christian Borntraeger
2010-03-08 15:33 ` David Newall
2010-03-08 16:00 ` Christian Borntraeger
2010-03-08 16:22 ` jim owens [this message]
2010-03-08 16:31 ` Greg Freemyer
2010-03-08 17:11 ` jim owens
2010-03-09 13:23 ` jim owens
2010-03-08 19:38 ` Valdis.Kletnieks
2010-03-08 20:48 ` jim owens
2010-03-09 16:19 ` David Newall
2010-03-08 5:47 ` [PATCH] ext4: allow defrag (EXT4_IOC_MOVE_EXT) in 32bit compat mode Eric Sandeen
2010-03-08 8:42 ` Akira Fujita
2010-03-12 7:01 ` [PATCH resend] " Christian Borntraeger
2010-04-02 21:48 ` [PATCH] " tytso
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=4B952437.8020607@gmail.com \
--to=owens6336@gmail.com \
--cc=a-fujita@rs.jp.nec.com \
--cc=borntraeger@de.ibm.com \
--cc=davidn@davidnewall.com \
--cc=jeff@garzik.org \
--cc=linux-ext4@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
/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).