VERITAS File System 3.5 (HP OnlineJFS/JFS 3.5) Administrator's Guide (August 2003)

Chapter 2
VxFS Performance: Creating, Mounting, and Tuning File Systems
Monitoring Free Space
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The “before” result is the degree of fragmentation prior to the reorganization. If the degreeof fragmentation is
approaching the figures for bad fragmentation, reduce the interval between fsadm runs. If the degree of
fragmentation is low, increase the interval between fsadm runs.
The “after” result is an indication of how well the reorganizer has performed. The degree of fragmentation
should be close to the characteristics of an unfragmented file system. If not, it may be a good idea to resize the
file system; full file systems tend to fragment and are difficult to defragment. It is also possible that the
reorganization is not being performed at a time during which the file system in question is relatively idle.
Directory reorganization is not nearly as critical as extent reorganization, but regular directory
reorganization will improve performance. It is advisable to schedule directory reorganization for file systems
when the extent reorganization is scheduled. The following is a sample script that is run periodically at 3:00
A.M. from cron for a number of file systems:
outfile=/usr/spool/fsadm/out.‘/bin/date +’%m%d’‘
for i in /home /home2 /project /db
do
/bin/echo "Reorganizing $i"
/bin/timex fsadm -F vxfs -e -E -s $i
/bin/timex fsadm -F vxfs -s -d -D $i
done > $outfile 2>&1