Messages in this thread | | | Date | Mon, 7 Dec 1998 21:18:35 -0500 | Subject | Re: atomicity | From | tytso@mit ... |
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Date: Sat, 5 Dec 1998 22:07:38 -0800 (PST) From: Tim Smith <tzs@tzs.net>
Unless I've accidently run my portable (written in straight ANSI C...works on Unix, Windows, and Mac!) file system fragmenter on it.
If you run this file system fragmenter not as root, so that you're not allowed to fill the last x percent of the filesystem, the filesystem won't get that fragmented.
That being said, in normal applications of the filesystem, ext2fs is fragmentation resistent. (Just as most watches are labelled as water resistant, and not waterproof.) However, in normal use fragmentation is much less of an issue than, say, the FAT filesystem. Furthermore, due to the readahead strategies that Linux uses, the performance degredation of a fragmentation isn't quite as bad as under DOS/Windows.
This is both good and bad features; the good side of it is that you rarely need to use a defragmenter. The bad side of it is that there isn't much incentive to develop good defragmenters, since it's rare that it's needed. For example, on my filesystems that I use personally, it's never been an issue, so I don't have much of an incentive to develop a good defragmenter. :-)
There is an ext2fs defragmenter out there, but it's extremely unsafe; it only works on an unmounted filesystem (obviously), but really bad things happen if you crash in the middle of the defragmentation operation.
- Ted
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