Storage Locations and Environment Variables

Several environment variables are defined on each ARSC system to provide convenient access to the available storage directories. We recommend you use these environment variables in batch scripts and on the command line to improve portability of your work within the ARSC environment. Because the variables have identical names and refer to the same types of storage on every system, it is possible to move scripts among ARSC systems with minimal changes by using the storage environment variables rather than explicit paths.

Name Notes Default Quota1 Purge Policy Back Up Policy
$HOME $HOME directories are intended for locally compiled executables and libraries,dot files, and small data sets. ARSC recommends that you avoid accessing $HOME in parallel jobs. 8GB3 not purged backed up
$CENTER $CENTER is a high performance Lustre file system available from all compute nodes. This is the preferred location to run large parallel jobs. 750GB3 30 day purge policy4 not backed up
$ARCHIVE $ARCHIVE directories are intended for long term storage of executables, large datasets, and compressed backups of important data. $ARCHIVE is only accessible from the HPC system login nodes and transfer queue. no quota not purged backed up
/center/d /center/d is an alternate directory used to store large group data sets. This directory is available upon request. Based on request and availability.3 not purged not backed up


  1. Individual user's are responsible to monitor their data usage. If usage exceeds the set quota further writes may fail.
  2. Requests for increased quotas should be sent to User Support.
  3. The "show_storage" command will display current usage for $HOME, $CENTER and /center/d directories.
  4. Data residing in $CENTER for inactive accounts may be purged without warning.
  5. The "show_storage" command is run automatically on login to warn when disk usage is approaching set quotas. This automatic check can be disabled by running "touch $HOME/.hush_storage"

Home directories are intended to contain files used for customizing your basic working environment only. Your home directory path is stored in the $HOME environment variable on every system. Home directories are unique to each platform and are routinely backed up. Small data files specific to a particular system belong here such as account configuration .cshrc/.login or .profile files. In many cases, if an executable compiled for a system is small enough, $HOME would be a logical place to store the executable.

Work directories are typically mounted locally or over a fast network connection. Following the "local cache" concept, doing your work in $CENTER instead of $ARCHIVE (where disk space is NFS mounted from a remote machine) will allow for faster I/O and save network bandwidth. $CENTER is available on most systems and always refers to the same style of storage space: a fast file system addressable by all nodes on that system.

As work directories are not backed up , please copy data that needs to be backed up to archive storage as soon as possible.

For more details on local storage configurations please see 'news storage' on the system you are using:

Archive directories are intended for data to be stored long term. Files in this directory are automatically backed up to tape after several hours. This filesystem provides the slowest access overall, however no quotas are set on this filesystem. See the following articles for a more information.

Please also be familiar with our storage policies:

Back to Top