Veritas File System v5.0.1 Administrator's Guide for HP-UX 11i v3 (5900-0082, June 2010)

The optimal period for scheduling of extent reorganization runs can be determined
by choosing a reasonable interval, scheduling fsadm runs at the initial interval,
and running the extent fragmentation report feature of fsadm before and after
the reorganization.
The before result is the degree of fragmentation prior to the reorganization. If
the degree of 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 improves 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
Thin Reclamation
Veritas File System (VxFS) supports reclamation of free storage on a Thin Storage
LUN. Free storage is reclaimed using the fsadm command or the vxfs_ts_reclaim
API. You can perform the default reclamation or aggressive reclamation. If you
used a file system for a long time and must perform reclamation on the file system,
Symantec recommends that you run aggressive reclamation. Aggressive
reclamation compacts the allocated blocks, which creates larger free blocks that
can potentially be reclaimed.
See the fsadm_vxfs(1M) and vxfs_ts_reclaim(3) manual pages.
Thin Reclamation is only supported on file systems mounted on a VxVM volume.
VxFS performance: creating, mounting, and tuning file systems
Monitoring free space
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