file fragmentation, torrents, azureus ?!?!?! Sluggish performance?

[t l]

'removing' the fragments from the files dramatically improved performance.

I did:
    cp ISO.iso better
    rm ISO.iso
    mv better ISO.iso
on all the isos created by the 2 torrents (binaries and src), and restarted
azureus. 

Wow.  What a difference.... I have my machine back.  User and idle time is way up, IO wait time is way down...

Now....if I only know what caused this.... Anyone?
   tom

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Subject: file fragmentation, torrents, azureus ?!?!?! Sluggish performance?
Date: Tue, 27 Apr 2004 19:39:25 -0800

I decided to try torrent-ing instead of ftp for test3 images.

A strange thing happened on my way to test3 CDs.
I ran the azureus client, and started torrents from the
dulog.duke.edu site.

The download of the first torrent (for the binaries) went
exceptionally fast. The second, for the sources, was a disaster: I
was getting about 10KB/sec at best down (up was doing better, at
about 80-100KB/sec). And, the machine was amazingling sluggish to
even simple shell commands.

A simple "ps agl" yielded the first 'gotcha': java had
grown to over 200MB (BEWARE of j2sdk-1_4_2_04.	There must be a
memory leak somewhere).

I killed azureus (and hence java), but things did NOT improve.	I
then noticed that the 'disk light' on the box was constantly on. My
ear against the case indicated non-stop disk activity.	(By this
time, commands like "md5sum *disc1.iso" were taking over
4-5 minutes to complete on an otherwise idle machine, accumulating
just 19 seconds of cpu time).

I then ran "filefrag *.iso" of the binaries.	Here is the
result:
    [root at fedora FC2-test3-binary-i386]# filefrag *.iso
    FC2-test3-i386-disc1.iso: 46138 extents found, perfection would
be 5 extents
    FC2-test3-i386-disc2.iso: 46739 extents found, perfection would
be 5 extents
    FC2-test3-i386-disc3.iso: 43183 extents found, perfection would
be 5 extents
    FC2-test3-i386-disc4.iso: 16279 extents found, perfection would
be 2 extents

Seems to me amazingly bad fragmentation. So it appears my poor disk
is thrashing around....
("cp FC2-test3-i386-disc1.iso" took 5 minutes of elapsed
time to complete.....)

"cp FC2-test3-i386-disc1.iso foobar.iso" produced a
"foobar.iso" with just 32 extents:
    [root at fedora better]# filefrag *.iso
    foobar.iso: 32 extents found, perfection would be 5 extents
or 46106 better than before ?!?!

Can this be expected behavior?	Who is the culprit: kernel, ext3,
azureus, java, ...?
Any one seeing this?  Suggestions?
   tom
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