# Global Directory Structure¶

## ULHPC File Systems Overview¶

Several File Systems co-exist on the ULHPC facility and are configured for different purposes. Each servers and computational resources has access to at least three different file systems with different levels of performance, permanence and available space summarized below

Directory Env. file system backup purging
/home/users/<login> $HOME GPFS/Spectrumscale yes no /work/projects/<name> - GPFS/Spectrumscale yes no /scratch/users/<login>$SCRATCH Lustre no yes
/mnt/isilon/projects/<name> - OneFS yes* no

## Global Home directory $HOME¶ Home directories provide a convenient means for a user to have access to files such as dotfiles, source files, input files, configuration files regardless of the platform. Refer to your home directory using the environment variable$HOME whenever possible. The absolute path may change, but the value of $HOME will always be correct. ## Global Project directory$PROJECTHOME=/work/projects/¶

Project directories are intended for sharing data within a group of researchers, under /work/projects/<name>

Refer to your project base home directory using the environment variable $PROJECTHOME=/work/projects whenever possible. ## Global Scratch directory$SCRATCH¶

The scratch area is a Lustre-based file system designed for high performance temporary storage of large files.

It is thus intended to support large I/O for jobs that are being actively computed on the ULHPC systems. We recommend that you run your jobs, especially data intensive ones, from the ULHPC scratch file system.

Refer to your scratch directory using the environment variable $SCRATCH whenever possible (which expands to /scratch/users/$(whoami)). The scratch file system is shared via the Infiniband network of the ULHPC facility and is available from all nodes while being tuned for high performance.

## Project Cold-Data and Archives¶

OneFS, A global low-performance Dell/EMC Isilon solution is used to host project data, and serve for backup and archival purposes. You will find them mounted under /mnt/isilon/projects.

Last update: January 19, 2021