During the installation, you are given the option to choose between classic spooling and Berkeley DB spooling server. If you choose Berkeley DB spooling, you are then given the option to spool to a local directory or to a separate host, known as a Berkeley DB spooling server.
While classic spooling is an option, you should see better performance using a Berkeley DB spooling server. Part of this performance increase is because the master host can make non-blocking writes to the database, but has to make blocking writes to the text file used by classic spooling. Other factors that may influence your decision are file format and data integrity. There is a greater level of data integrity when you write to the Berkeley DB, rather than to a text file. However, a text file stores data in a format that humans can read and edit. Normally, you do not need to read these files, but the spooling directory contains the messages from the system daemons, which can be useful during debugging.