The /var/run File System
check here
http://docs.sun.com:80/ab2/coll.47.1...Enc=iso-8859-1
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A new TMPFS-mounted file system, /var/run, is the repository for temporary "system files" that are
not needed across system reboots in this Solaris release and future releases. The /tmp directory
continues to be repository for "non-system temporary files".
Because /var/run is mounted as a memory-based file system rather than a disk-based file system,
updates to this directory do not cause unnecessary disk traffic that would interfere with systems
running power management software.
The /var/run directory requires no administration. You may notice that it is not unmounted with the
umount -a or the umountall command.
For security reasons, /var/run is owned by root.
Hope this help