It is a heavily used database that affects all processes on the server and is used by most system procedures. It is automatically installed on the master device. If more space is needed, you can expand tempdb to other devices. If you expect tempdb to be quite active, place it on a disk—the fastest available—that is not used for other important database activity. .
On some UNIX systems, I/O to operating system files is significantly faster than I/O to raw devices. tempdb is always re-created, rather than recovered, after a shutdown; therefore, you may be able to improve performance by moving tempdb onto an operating system file instead of a raw device. Test this on your own system.
See Chapter 6, “Temporary Databases,” for more placement advice for tempdb.
