Добрый день!В соляре /tmp это виртуальная файловая система (даже не ufs !!!) и размер ее зивисит от размера свапа.
Рекомендую почитать сановский документ Devices and File System на docs.sun.com
Кусок этой доки по /tmp :
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:
The TMPFS file system can run out of space, just as regular file systems do.
Because TMPFS allocates swap space to save file data (if necessary), some
programs might not execute because of insufficient swap space.
For information about creating TMPFS file systems, see Chapter 18. For information
about increasing swap space, see Chapter 21.