From: Theodore Tso <tytso@mit.edu>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: linux-fsdevel@vger.kernel.org
Subject: Re: Does \"32.1% non-contigunous\" mean severely fragmented?
Date: Fri, 19 Oct 2007 14:52:22 -0400 [thread overview]
Message-ID: <20071019185222.GB751@thunk.org> (raw)
In-Reply-To: <200710190149.l9J1n3Ti083212@www262.sakura.ne.jp>
On Fri, Oct 19, 2007 at 10:49:03AM +0900, Tetsuo Handa wrote:
> /data/VMware: 349/19546112 files (32.1% non-contiguous), 31019203/39072080 blocks
>
> Does non-contiguous mean fragmented?
> If so, where is ext3defrag?
Not necessarily; it just means that 32% of your files have at least
one discontinuity. Given the ext3 layout, by definition every 128
megs there will be a discontinuity because of the metadata at the
beginning of every single block group. You have a small number of
files on your system (349) occupying an average of 348 megabytes. So
it's not at all surprising that the contiguous percentage is 32%.
The recent Flex BG feature that was recently pulled into 2.6.23-git14
for ext4 is desgined to avoid this issue, but a seek every 128 megs is
for most workloads not a big deal and will hopefully not cause you any
problems.
- Ted
next prev parent reply other threads:[~2007-10-19 18:52 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-19 1:49 Does \"32.1% non-contigunous\" mean severely fragmented? Tetsuo Handa
2007-10-19 18:52 ` Theodore Tso [this message]
2007-10-20 3:39 ` Does "32.1% non-contiguous" " Tetsuo Handa
2007-10-20 13:17 ` Theodore Tso
2007-10-22 11:58 ` Tetsuo Handa
2007-10-22 13:02 ` Theodore Tso
2007-10-23 10:38 ` Tetsuo Handa
2007-10-23 12:34 ` Theodore Tso
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