ARC Storage Terms of Use

There are several options for disk storage on the ARC Cluster. Please review this section carefully to decide where to place your data. Contact systems staff at support@hpc.ucalgary.ca if you have any questions. As this is a limited resource, please use the space responsibly. Disk space on the ARC Cluster should not be used as archival storage, nor should it be used as a backup (2nd copy location) for other systems (e.g. desktops, laptops, etc.).

Summary of File Storage Options

File System	Type	Snapshots	Backups	Quota
/home	NetApp FAS8200, NFS	7 days	No	500 GB/user
/scratch	NetApp FAS8200, NFS	None	No	15 TB/user
/work	NetApp FAS8200, NFS	7 days	No	By request/group
/bulk	NetApp FAS2720, NFS	7 days	No	By request/group
/tmp	Local	None	No	100 GB

Currently all users are responsible for managing their own backups.

Performance

Bulk	Work
Single node streaming R/W 540/730 MB/s Aggregate (multi-node) R/W 4140/4400 MB/s Untar Linux kernel (~39000 files): 3:09 (m:ss)	Single node streaming R/W 620/750 MB/s Aggregate (multi-node) R/W 6131/5616 MB/s Untar Linux kernel (~39000 files): 2:30 (m:ss)

/home

Each user has a home directory called /home/username. The /home file system has a quota of 500 GB per user which cannot be increased, and seven days of snapshots.

/scratch

/scratch is intended for temporary data for the duration of the job. Directories in /scratch are created when a user job starts. The naming of the directory is /scratch/JOBID, where JOBID is the job id that is assigned by Slurm. It is expected that jobs clean up the contents of their scratch directory when the job completes, as part of the Slurm batch job. Any files older than 10 days will be automatically deleted. Each user can store up to a maximum of 15 TB in /scratch. However, due to the shared nature of /scratch, we cannot make any guarantees that the full 15 TB will be available at any given time. If /scratch becomes more than 75% full, we reserve the right to delete the files as needed.

/work

/work is intended for projects whose data requirements exceeds the storage allocation for /home. /work is requested by the Principal Investigator (PI) on behalf of the entire group. The request should be made as needed. Please contact us at support@hpc.ucagary.ca for further assistance. 7-day snapshots are available.

/bulk

/bulk is intended for large allocations that have lesser I/O needs intended for streaming reads and writes. /bulk is requested by the Principal Investigator (PI) on behalf of the entire group. The request should be made as needed. Please contact us at support@hpc.ucagary.ca for further assistance. 7-day snapshots are available. Portion of /bulk file system will be available to scientific instruments on campus, on a request basis. Please contact support@hpc.ucalgary.ca for further assistance.

Best Practices

Bad	Good
Submitting many jobs without a good understanding of how much data it would generate Directories with millions of files Excessively long file names Short descriptive names for files The /bulk or /work file systems should not be used as a temporary directory for applications Multiple copies of same data between individual researchers Using ARC storage for archiving	Run a test job, and scale the data requirements appropriately Use appropriate file formats or tools that reduce the number of files Use /scratch or /tmp file systems instead Request for a shared space Contact support@hpc.ucalgary.ca to discuss requirements

Please note that we reserve the right to perform emergency and critical maintenance at any moment with minimal warning.