System Administration Guide: Devices and File Systems

Temporary File System

The temporary file system (TMPFS) uses local memory for file system reads and writes. Typically, using memory for file system reads and writes is much faster than using a UFS file system. Using TMPFS can improve system performance by saving the cost of reading and writing temporary files to a local disk or across the network. For example, temporary files are created when you compile a program. The OS generates a much disk activity or network activity while manipulating these files. Using TMPFS to hold these temporary files can significantly speed up their creation, manipulation, and deletion.

Files in TMPFS file systems are not permanent. These files are deleted when the file system is unmounted and when the system is shut down or rebooted.

TMPFS is the default file system type for the /tmp directory in the Solaris OS. You can copy or move files into or out of the /tmp directory, just as you would in a UFS file system.

The TMPFS file system uses swap space as a temporary backing store. If a system with a TMPFS file system does not have adequate swap space, two problems can occur:

For information about creating TMPFS file systems, see Chapter 18, Creating UFS, TMPFS, and LOFS File Systems (Tasks). For information about increasing swap space, see Chapter 21, Configuring Additional Swap Space (Tasks).