Temporary Disk Space

There are several places where users can temporarily store data.


Temporary storage locations are not backed up and may be removed without notice.


Files put in the /tmp directory are only accessible on the machine on which they were created and are automatically wiped everytime the computer is rebooted. Files may also be deleted with little or no warning if resources become scarce. However, if you need a large amount of disk space for a short amount of time, /tmp provides a solution which does not need any staff intervention. Remember that there is no guarantee that files stored in /tmp are safe. Do not use /tmp for data that that is difficult or expensive to re-create.

No special permissions are required to use /tmp. To reference your files using /tmp, use ‘/tmp’ as the prefix to the name of the file, for example ‘/tmp/myfile’. If you are storing more than a handful of files, reduce the clutter by using a subdirectory of /tmp named with your account name, for example ‘/tmp/username/myfile’.

The limit to the amount of storage a user can take up is the physical limitation of the partition. However, if /tmp is full, editors, compilers, and many other programs will not work or behave erratically. To find out how much space is available in /tmp on your system, type ‘df -k /tmp’. Do not use /tmp if less than 30% of the space is available. Remove files when they are no longer needed.

/var/tmp, /Users/Shared

The /var/tmp directory functions similarly to /tmp, however, files are not automatically removed after the machine is rebooted. This directory does get erased, however, whenever the workstation needs to be reinstalled or reconfigured. Otherwise, the same policies that apply to /tmp apply to /var/tmp.

The /Users/Shared directory functions identically to /var/tmp, except it is only found on our Macintosh computers.


The /var/tmp/scratch directory exists on some workstations that have secondary disks. This directory functions similarly to /var/tmp, however, it does not get erased when the computer is reinstalled or reconfigured.


Directories under /scratch/public can be used for projects requiring large files that are modified frequently. The scratch directories exist on the file server and not on the local workstations, however if space becomes limited we may automatically compress/gzip files or (if time permitting) ask users to either remove or archive files that are no longer needed in order to make room for other users needs. Files that are not actively being used and are compressible should be stored in a compressed format.