In UNIX, an inode represents the information
stored by the OS for an individual file for the
UNIX file system (remember, a file can represent
a device as well). Typically, the maximum
number of inodes is fixed at file system
creation time. If you find you are running
out of inodes often, you may have to adjust
the system tunable parameter and rebuild your
kernel. Normally, this value is set to 3 or
4 times the maximum number of files allowed
for a file system (since stdin, stdout, stderr
and sockets require inodes as well). Under normal
circumstances, you should not run out of inodes
before you run out of file space (or max_files).
This can happen if you are creating a LARGE
number of very small files.
I hope this helps