Each compute node has its own local scratch filesystem. Users may read from and write to this using their own exclusive directory at /localscratch/Users/<HawkID>.
In addition to local storage, each HPC cluster has its own large, shared filesystem mounted across all its nodes via NFS. Analogously, users can read from and write to this using their own exclusive directory at /nfsscratch/Users/<HawkID>.
Scratch filesystems are a shared resource available for the convenience of all users. Therefore, files on these filesystems are subject to deletion after a certain lifespan as determined by the HPC policy committee. Home account storage and purchased storage are not subject to this policy.
On /localscratch, the allowed file lifespan is 30 days after the file was last accessed, and a file's age is the time elapsed since its access timestamp ("atime"). An automated cleanup process will run periodically on each node to delete files whose atime has reached the maximum lifespan. It is also expected that large amounts of data put on /localscratch are cleaned up at the end of a job. Otherwise, the node become unavailable. A node left in this condition will have /localscratch clean entirely, irrespective of time stamps, to make the node available again.
On /nfsscratch, the allowed file lifespan is 60 days after first being written to an /nfsscratch filesystem, and a file's age is the time elapsed since its creation timestamp ("crtime") which is tracked on the fileserver. An automated cleanup process will run periodically on the server to delete files whose crtime has reached the maximum lifespan.
Altering or duplicating files solely to circumvent the scratch cleanup process is against policy. Please make legitimate use of scratch filesystems, then move your intermediate and final results to stable storage in accordance with policy.
Please contact email@example.com with any questions or for assistance with this.
ls -l file
ls -lc file
ls -lu file
All of these timestamps can be different for a single file. Most file and archive utilities will maintain the first 3 timestamps, either by default or optionally. This includes using archive mode ('-a') with either 'cp' or 'rsync'. However, note that no utility can affect a file's crtime at all over NFS.