$TMPDIR - temorary file system

In the world of Unix one normally thinks of temporary files as being written to the local file system /tmp (TMPDIR).  This is different to the HOME file system which is mounted to each computer in the cluster system from a central location via NFS and to the BIGWORK scratch file system which is mounted to each computer from a central location via Lustre.

The /tmp file system is accessible to all users of the system, however files written by a given user can only be deleted by that user.  Files which have been inactive for 10 days (neither read from nor written to) will be automatically deleted.

Because the /tmp directory is accessible to all users, it can happen that more than one user attempts to write to the same file (for example /tmp/test).  Therefore, users are advised to be careful in choosing filenames when writing to the /tmp file system.  A good idea is to create a directory with the same name as your username and then write your temporary files inside this directory.

Because the /tmp file system is local to a given compute server, there is a varying amount of available disk space across the entire cluster system.  One should also note that one shares this space with other users of the cluster system and due consideration is therefore necessary.