File Systems
Horizon has two major file systems of its own, which each user can access from any Horizon node through the variables $HOME and $SCRATCH. These are NFS-based flash file systems from VAST Data. The $HOME file storage area is relatively small, but it is backed up regularly; while the much larger $SCRATCH storage area is designed for short-term use, as any files in $SCRATCH are subject to periodic purge.
A third file system, $WORK, is also planned for Horizon for late 2026. It is globally connected to all of TACC's HPC resources and it is designed for high performance as well as high capacity.
Remember that the Good Conduct guidelines state that you should not stress the shared filesystems.
TACC recommends that any and all job related data, both input and output, be stored on $SCRATCH and not $WORK. TACC found that due to NVIDIA's unified memory architecture, the Grace Hopper nodes on Vista would use GPU memory as a file system cache, and this memory occasionally could not be reclaimed after an application exits, resulting in a hung node that required a reboot.
File System Details
| Filesystem | $HOME |
$WORK |
$SCRATCH |
|---|---|---|---|
| Intended Use | Storing source code and important files | Storing large files, packages, and software | Storing large files, I/O for jobs |
| Command-line Shortcuts to Access | cdh, cd ~, or cd |
cdw |
cds |
| Quota (soft limit)1 | 49GB (decimal units) | TBD | No restrictions |
| Limit (hard limit)1 | 50GB (decimal units) | TBD | No restrictions |
| Maximum Files Allowed1 | 500k (decimal units) | TBD | No restrictions |
| Backed Up | Yes | No | No |
| Purged | No | TBD | Yes, all files not accessed in 10 days2 |
| Shared Between TACC Systems | No | TBD | No |
1 Quotas and limits can be checked with quota -s -f /home1, e.g.; note that quotas and limits on space are reported in MiB (mebibytes) rather than decimal units.
2 Access time is based on a modification or read of the file, or execution of the file on a compute node. For more information, see the Horizon User Guide: File Systems.
Navigating File Systems from TACC Training
CVW material development is supported by NSF OAC awards 1854828, 2321040, 2323116 (UT Austin) and 2005506 (Indiana University)