From: Chris Mason <chris.mason@oracle.com>
To: Paul Komkoff <i@stingr.net>
Cc: linux-btrfs <linux-btrfs@vger.kernel.org>
Subject: Re: btrfs defrag: how does it work?
Date: Thu, 20 Jan 2011 16:38:18 -0500 [thread overview]
Message-ID: <1295559487-sup-9500@think> (raw)
In-Reply-To: <AANLkTikcNy1FdRjLu=bDpE=A7krUysmV2uLwN9jh4AF2@mail.gmail.com>
Excerpts from Paul Komkoff's message of 2011-01-19 17:31:56 -0500:
> On Wed, Jan 19, 2011 at 9:25 PM, Chris Mason <chris.mason@oracle.com>=
wrote:
> > The defrag code doesn't actually defrag. =C2=A0It opens up the file=
and
> > recows all the extents and then the delayed allocation code jumps i=
n and
> > makes the biggest possible extent that it can.
> >
> > The reason why you're still seeing extents after running the defrag
> > command is because the file hasn't been written yet, so the delayed
> > allocation code hasn't kicked in.
> >
> > If you use btrfs fi defrag -f it'll trigger writeback on the file a=
nd
> > you should see the results of the defrag sooner.
>=20
> I tried, and just tried it again, with the same file. I even tried
> doing btrfs fi sync in random order. No matter what I do, it's still
> 132 extents :)
Are you using compression?
-chris
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" =
in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
next prev parent reply other threads:[~2011-01-20 21:38 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-19 19:58 btrfs defrag: how does it work? Paul Komkoff
2011-01-19 21:25 ` Chris Mason
2011-01-19 22:31 ` Paul Komkoff
2011-01-19 22:49 ` Mitch Harder
2011-01-20 21:38 ` Chris Mason [this message]
2011-01-22 13:38 ` Paul Komkoff
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=1295559487-sup-9500@think \
--to=chris.mason@oracle.com \
--cc=i@stingr.net \
--cc=linux-btrfs@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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.