Following your discussion about fragmentation I've been googling 
around for some facts, benchmarks and tools and I think you might 
want to take a look:

First according to wikipedia http://en.wikipedia.org/wiki/ReiserFS:

"Tail packing, a scheme to reduce internal fragmentation. Tail packing, 
however, has a significant performance impact; Namesys recommends 
disabling the feature in performance-critical applications. "

"There is no known way to defragment a ReiserFS filesystem, aside 
from a full dump and restore. However ReiserFS v4 has a repacker 
that takes care of file fragmentation."

"Gentoo Forum Link - Contains an interesting discussion of fragmentation 
in reiserFS, includes a script which measures fragmentation and links 
to a script that defragments quite well. "

And here is the link: 
http://forums.gentoo.org/viewtopic-t-429915-postdays-0-postorder-asc-start-0.html
The script is universal and shuld work for all filesystems.

Very interesting benchmark of different filesystems fragmentation:
http://www.informatik.uni-frankfurt.de/~loizides/reiserfs/agesystem.html#500reiser

Also interesting interview with JFS, ReiserFS and XFS creators (including
questions about fragmentation policy):
http://www.osnews.com/story.php?news_id=69

Detailed explanation of diffrent kinds of fragmentation:
http://linuxgazette.net/issue55/florido.html

Defragmenting ext3 with defrag:
http://www.newsforge.com/os/03/10/07/2028234.shtml

And that's all. I hope that'll help the discussion.

-- 
Rafal Szczepaniak (LanRat)

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