By default, onShore TimeSheet will not be backed up, this is up to the onShore TimeSheet administrator to initialize. However, it it highly encouraged that backup is done at least once a week if your company's work flow and billing highly depends on onShore TimeSheet, not because onShore TimeSheet is inherently unstable but because accidents happen, database deletions, database corruption, disk corruption, etc. may necessitate a partial or full database restore.
Tape backups of the filesytem where the database keeps its data files will protect you from losing the database completely, but we highly suggest using the timesheet-dumpscript which has been included in the onShore TimeSheet distribution for backup operations. This script uses pg_dump (1) to dump the database into a script file containing the SQL commands necessary for recreating the database. Storing the database into this ASCII format allows you to easily restore the database using timesheet-load, which in turn runs the scripts that was dumped with psql (1), which will re-create or replace any lost data. Also, you could use the dumps from timesheet-dump for importing or creating a duplicate database on another server.