Automatically Purging Job History in SCVMM 2008
To automatically purge Job History in SCVMM 2008 add the TaskGC registry key to HKEY_LOCAL_MACHINE\Software\Microsoft\Microsoft System Center Virtual Machine Manager Server\Settings\SQL
The REG_DWORD value is in days. Once you restart the VMM service jobs will be automatically be purged from the database.
Patrick Lownds