Symantec Endpoint Protection 11 (short: SEP11) has a database in which it stocks everything from client properties, virus definitions and more. At the installation, you could either select to use an external data source, or its internal database format. When the database is in service for a while, it can grow very large, depending on the number of clients you've got. But it is possible to shrink (= compact) it, which, in certain cases, could save you several hundreds of MB.
SEPM comes with a tool to perform the compacting and shrinking, called dbunload. It is installed along with the console. To shrink the database, perform the steps below. Depending on your installation path (and whether you're running 32-bit or 64-bit Windows), the paths mentioned need to be changed accordingly. The steps below show the default paths.
cd \Program Files\Symantec\Symantec Endpoint Protection Manager\ASA\win32
dbunload -c "dbf=C:\Program Files\Symantec\Symantec Endpoint Protection Manager\db\sem5.db;start=dbsrv9;uid=dba;pwd=password_set_during_install" -ar