New scratch system based on XFS has been put into service and is available under /scratch3. Every user has a personal directory on /scratch3. The /scratch3 file system is not backed up and all files not accessed for last 30 days will be removed daily.

We have also installed small very fast scratch system which is available under /fast_scratch. This system is based on XFS and SSD disks and has much smaller capacity. Due to the capacity, /fast_scratch will be available per project after CU-CAT approval.

The available scratch systems on Palmetto are:

Location Capacity Description
/local_scratch varies by phase local temporary space on each compute node
/scratch1 233 TB OrangeFS based parallel scratch system
/scratch2 160 TB global ZFS based scratch system
/scratch3 129 TB global XFS based scratch system
/fast_scratch 8.5 TB global XFS SSD based scratch system

To choose the most appropriate scratch file system for your application, we recommend running benchmark to test the I/O performance on /local_scratch, /scratch1, /scratch2 and /scratch3.

/scratch1 will be most appropriate for applications using parallel I/O. If your application uses small I/O and not utilizes parallel I/O, it may be more efficient to use /local_scratch, /scratch2 or /scratch3.

If you need any help in determining the most appropriate scratch file system for your application please contact