How to shrink the database
From Tech-Wiki
If the partition is full delete some old log files to make some space.
Change the number of days
Configure > Administration > Maintenance Reduce the number of days in the Cleanup Historical Data table
Start the database
start db
Start the deletion of the old data
/usr/local/st/st_monitor tail -F /var/log/st/st_monitor
Reclaim the database space (vacuum the DB)
psql securetrack -Upostgres -c "VACUUM FULL"