1. Launch Terminal.app
2. Stop the software update service first.
serveradmin stop swupdate
3. View the current storage location:
serveradmin settings swupdate:updatesDocRoot
4. Set a new location. You MUST use the quotation marks in the path.
serveradmin settings swupdate:updatesDocRoot = "/Path/to/swupdate/store/"
5. Check to make sure the path was updated successfully.
serveradmin settings swupdate:updatesDocRoot
6. Start the software update service.
serveradmin start swupdate