tempdb is automatically installed on the master device. If more space is needed, tempdb can be expanded to other devices. If tempdb is expected to be quite active, place it on a disk that is not used for other important database activity. Use the fastest disk available for tempdb. It is a heavily used database that affects all processes on the server.
On some UNIX systems, I/O to operating system files is significantly faster than I/O to raw devices. Since tempdb is always re-created, rather than recovered, after a shutdown, you may be able to improve performance by altering tempdb onto an operating system file instead of a raw device. You should test this on your own system.
See Chapter 18, “tempdb Performance Issues,” for more placement issues and performance tips for tempdb.