The TMPFS file system is activated automatically in the Oracle Solaris environment by an entry in the /etc/vfstab file. The TMPFS file system stores files and their associated information in memory (in the /tmp directory) rather than on disk, which speeds access to those files. This feature results in a major performance enhancement for applications such as compilers and DBMS products that use /tmp heavily.
The TMPFS file system allocates space in the /tmp directory from the system's swap resources. This feature means that as you use up space in the /tmp directory, you are also using up swap space. So, if your applications use the /tmp directory heavily and you do not monitor swap space usage, your system could run out of swap space.
Do use the following if you want to use TMPFS, but your swap resources are limited:
Mount the TMPFS file system with the size option (–o size) to control how much swap resources TMPFS can use.
Use your compiler's TMPDIR environment variable to point to another larger directory.
Using your compiler's TMPDIR variable only controls whether the compiler is using the /tmp directory. This variable has no effect on other programs' use of the /tmp directory.