Info
Performance enhancement for running dt tool scripts
The desktop server has a new option to relocate the .Desktop database outside of the volume directory. This has the following advantages: - Avoid problems when the volume runs out of free disk space. - Performance enhancement using the desktop database on an idle disk. - Performance enhancement when using ZFS, moving the desktop database to UFS avoids timeout errors due to heavy disk flushing of ZFS.
The desksrv preference "desktoplocation" must be set to change the location of the .Desktop file. The location can be an absolute or (HELIOSDIR) relative path to the new area, where a subfolder tree with the name of the original volume path will be created automatically, containing the .Desktop file.
After the preference is set, the desksrv must be restarted.
There will be no automatic volume rebuilds. All volumes will keep their existing volume desktop databases, unless a rebuild is issued explicitly.
Only a rebuild in HELIOS Admin or using "rebuild -f" will re-create the .Desktop file in its new location. The old .Desktop will be turned into a symlink to the new location. The symlink can also be modified to point to a different, custom location.
Preference example with relative path: The existing volumepath is /data/helios # prefvalue -k Programs/desksrv/desktoplocation -t str "var/desktops" This will create the volume .Desktop file in $HELIOSDIR/var/desktops/data/helios/.Desktop
Preference example with absolute path: The existing volumepath is /data/helios # prefvalue -k Programs/desksrv/desktoplocation -t str "/desktops" This will create the volume .Desktop file in /desktops/data/helios/.Desktop
Notes:
NFS --- If a volume is used also remotely via NFS by dt tools, make sure that both volume data and .Desktop file are accessible over NFS at the path specified. Otherwise you could end up with a separate volume desktop which is only current on the second system where "dt" is used to access volume data over NFS.
Existing symlinks ----------------- Once a volume desktop database file is relocated by a symlink, a "rebuild -f" will honor that link, and recreate a new desktop file at the destination of the link as long the "desktoplocation" preference is active.
If the path of the "desktoplocation" is changed, the existing ".Desktop" symlinks must be removed manually to use the new location, otherwise the old symlink will be used. Make sure that the desktop database is not in use at that time you remove the link.
If the "desktoplocation" preference is deleted, further "rebuild -f" will not honor symlinks anymore and will create desktops in the volume directory. |