From: Theodore Tso <tytso@mit.edu>
To: Curt Wohlgemuth <curtw@google.com>
Cc: Andreas Dilger <adilger@sun.com>,
ext4 development <linux-ext4@vger.kernel.org>
Subject: Re: Question on block group allocation
Date: Mon, 27 Apr 2009 06:42:21 -0400 [thread overview]
Message-ID: <20090427104221.GB9059@mit.edu> (raw)
In-Reply-To: <6601abe90904262229w602e17d8s51ceae05c2895ce5@mail.gmail.com>
On Sun, Apr 26, 2009 at 11:29:39PM -0600, Curt Wohlgemuth wrote:
>
> The random read throughput on the 10GB file went from ~16 MB/s to ~22
> MB/s after Andreas' patch; the total fragmentation of the file was
> much lower than before his patch.
>
> However, the number of extents went up by quite a bit (I don't have
> the debugfs output in front of me at the moment, sorry). It seemed
> that no extent crossed a block group; I didn't have time to see if
> Andreas' patch disabled flex BGs or not, as to what was going on.
Try running e2fsck with the "-E fragcheck" option, and then capture
e2fsck's stdout. It will help with the grunt work of doing the
analysis, in terms of displaying the details of all of the files which
are discontiguous.
- Ted
next prev parent reply other threads:[~2009-04-27 10:42 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-23 16:41 Question on block group allocation Curt Wohlgemuth
2009-04-23 19:08 ` Andreas Dilger
2009-04-23 22:02 ` Curt Wohlgemuth
2009-04-27 2:14 ` Theodore Tso
2009-04-27 5:29 ` Curt Wohlgemuth
2009-04-27 10:42 ` Theodore Tso [this message]
2009-04-27 22:40 ` Theodore Tso
2009-04-29 18:38 ` Curt Wohlgemuth
2009-04-29 19:37 ` Theodore Tso
2009-04-29 20:21 ` Curt Wohlgemuth
2009-04-29 21:20 ` Theodore Tso
2009-04-29 21:50 ` Theodore Tso
2009-04-29 22:29 ` Curt Wohlgemuth
2009-05-01 4:39 ` Theodore Tso
2009-05-04 15:52 ` Curt Wohlgemuth
2009-04-29 19:16 ` Theodore Tso
2009-04-27 23:12 ` Andreas Dilger
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