[Linux-cluster] defragmentation.....

[Alan Brown]

This is interesting too. note the variation in extents (the file is a 
piece of marketing fluff, name is unimportant)


$ df -h .
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/VolGroupBeast03-LogVolUser1
                       250G  113G  138G  45% /stage/user1

$ ls -l SUMO-SATA-Competitive-Positioning-v1.ppt
-rw-r--r-- 1 ajb2 computing 3746304 Nov  8  2007 
SUMO-SATA-Competitive-Positioning-v1.ppt

$ rsync SUMO-SATA-Competitive-Positioning-v1.ppt 
SUMO-SATA-Competitive-Positioning-v1.ppt.new

$ filefrag SUMO-SATA-Competitive-Positioning-v1.ppt*
SUMO-SATA-Competitive-Positioning-v1.ppt: 915 extents found
SUMO-SATA-Competitive-Positioning-v1.ppt.new: 153 extents found

$ rsync SUMO-SATA-Competitive-Positioning-v1.ppt 
SUMO-SATA-Competitive-Positioning-v1.ppt.new
$ filefrag SUMO-SATA-Competitive-Positioning-v1.ppt*
SUMO-SATA-Competitive-Positioning-v1.ppt: 915 extents found
SUMO-SATA-Competitive-Positioning-v1.ppt.new: 73 extents found

$ rsync SUMO-SATA-Competitive-Positioning-v1.ppt 
SUMO-SATA-Competitive-Positioning-v1.ppt.new
$ filefrag SUMO-SATA-Competitive-Positioning-v1.ppt*
SUMO-SATA-Competitive-Positioning-v1.ppt: 915 extents found
SUMO-SATA-Competitive-Positioning-v1.ppt.new: 12 extents found

$ rsync SUMO-SATA-Competitive-Positioning-v1.ppt 
SUMO-SATA-Competitive-Positioning-v1.ppt.new
$ filefrag SUMO-SATA-Competitive-Positioning-v1.ppt*
SUMO-SATA-Competitive-Positioning-v1.ppt: 915 extents found
SUMO-SATA-Competitive-Positioning-v1.ppt.new: 16 extents found

$ rsync SUMO-SATA-Competitive-Positioning-v1.ppt 
SUMO-SATA-Competitive-Positioning-v1.ppt.new
$ filefrag SUMO-SATA-Competitive-Positioning-v1.ppt*
SUMO-SATA-Competitive-Positioning-v1.ppt: 915 extents found
SUMO-SATA-Competitive-Positioning-v1.ppt.new: 9 extents found

$ rsync SUMO-SATA-Competitive-Positioning-v1.ppt 
SUMO-SATA-Competitive-Positioning-v1.ppt.new
$ filefrag SUMO-SATA-Competitive-Positioning-v1.ppt*
SUMO-SATA-Competitive-Positioning-v1.ppt: 915 extents found
SUMO-SATA-Competitive-Positioning-v1.ppt.new: 16 extents found

$ cp SUMO-SATA-Competitive-Positioning-v1.ppt 
SUMO-SATA-Competitive-Positioning-v1.ppt.new
cp: overwrite `SUMO-SATA-Competitive-Positioning-v1.ppt.new'? y
$ filefrag SUMO-SATA-Competitive-Positioning-v1.ppt*
SUMO-SATA-Competitive-Positioning-v1.ppt: 915 extents found
SUMO-SATA-Competitive-Positioning-v1.ppt.new: 5 extents found

$ cp SUMO-SATA-Competitive-Positioning-v1.ppt 
SUMO-SATA-Competitive-Positioning-v1.ppt.new
cp: overwrite `SUMO-SATA-Competitive-Positioning-v1.ppt.new'? y
$ filefrag SUMO-SATA-Competitive-Positioning-v1.ppt*
SUMO-SATA-Competitive-Positioning-v1.ppt: 915 extents found
SUMO-SATA-Competitive-Positioning-v1.ppt.new: 16 extents found

All these commands were executed in a 30 second period.