The Temporary File System (TMPFS) uses local memory for file system reads and writes, which is typically much faster than 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, and the operating system generates a lot of disk 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. They 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 operating environment. 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:
The TMPFS file system can run out of space, just as a regular file system can fill up.
Because TMPFS allocates swap space to save file data (if necessary), some programs might not execute because there is not enough swap space.
See Chapter 35, Creating File Systems (Tasks) for information about creating TMPFS file systems. See Chapter 38, Configuring Additional Swap Space (Tasks) for information about increasing swap space.