Running Out of Space in the Root Filesystem

For systems that have separate Root and Usr filesystems, running out of disk space on the Root filesystem can occur for several reasons:

New software options that place files in the Root filesystem have been installed.
A new IRIX release that requires more disk space in the Root filesystem has been installed.
Files created while filesystems were unmounted have been unintentionally placed in the Root filesystem instead of their intended filesystem. For example, say that the Usr filesystem is unmounted and the file /usr/tempfile is created. When the Usr filesystem is mounted at /usr, the file /usr/tempfile isn't accessible, but it is still using disk space.
Applications that create files in /tmp are creating many files or very large files that fill up the Root filesystem.

Several possible courses of action when the Root filesystem is too full are listed below. You may want to pursue several of them.

Check for hidden files. Unmount filesystems other than the Root filesystem (you may find this easiest to do from the miniroot) and list the contents of each of the mount point directories.
Check the /lost+found directory. You may find that large files have accumulated there.
Increase the size of the Root filesystem by combining the Root and Usr filesystems or by making the Root filesystem larger by taking disk space from the Usr filesystem.
Identify applications that are creating files in /tmp and cause the most problems, and configure them to use /usr/tmp instead of /tmp for temporary files. Most applications recognize the TMPDIR environment variable, which specifies the directory to use instead of the default. For example, with csh:
% setenv TMPDIR /usr/tmp
With sh:

% TMPDIR=/usr/tmp ; export TMPDIR
Make /tmp a mounted filesystem. (See the section "Mount a Filesystem as a Subdirectory" in Chapter 3.) You can "carve" a /tmp filesystem out of other filesystems if need be.