Scratch and Temporary Space

Users can create a directory in scratch directories for short-term use of large files. Any scratch file not modified in 28 days will automatically be deleted. The scratch filesystems are not backed up or snapshotted, so any deleted file cannot be recovered. Extensions on this 28-day policy are available on a case-by-case basis - please email extension requests to

Scratch space is useful for jobs requiring significant amount of disk access. Long-term storage is more appropriately suited to home or group space.

The Itasca and Calhoun HPC systems each have their own scratch spaces. See the pages for these systems for information on file retention in /scratch.

Other scratch filesystems are shared between all lab workstations and remote lab resources. Available shared scratch filesystems for lab use are as follows: /scratch, /scratch1, /scratch2, /scratch3, and /scratch4. They are all mounted from disk and have no quotas. It is recommended to check and see which one has the most space available before creating a new directory in scratch:

user@login% cd /scratch;cd /scratch1; cd /scratch2; cd /scratch3; cd /scratch4; cd
user@login% df -h
Filesystem Size Used Avail Use% Mounted on
... 4.0T 2.7T 1.4T 66% /project/scratch4 1.2T 934G 267G 78% /project/scratch1 10T 7.9T 2.2T 79% /project/scratch2 9.4T 4.2T 5.2T 45% /project/scratch 9.0T 2.7T 6.4T 30% /project/scratch3

Each lab workstation also has its own /scratch.hostname filesystem, which exists on local disk and therefore may be faster, at the expense of only being available on that workstation.

Any files stored (by software or by users) in temporary directories local to a specific machine, such as /tmp and /var/tmp, may be deleted at any time.