User-Centric Data Storage


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The following table summarizes user-centric storage areas available on OLCF resources and lists relevant polices.

User-Centric Storage Areas

Area Path Type Permissions Quota Backups Purged Retention On Compute Nodes
User Home /ccs/home/[userid] NFS User set 50 GB Yes No 90 days Read-only
User Home, Moderate Enhanced Projects /gpfs/arx/[projid]/home/[userid] Spectrum Scale 700 50 TB No Yes Subject to Purge Read/Write
User Archive [1] /home/[userid] HPSS User set 2TB No No 90 days No
User Archive [2] /home/[userid] HPSS 700 N/A N/A N/A N/A No


[1]This entry is for legacy User Archive directories which contained user data on January 14, 2020. There is also a quota/limit of 2,000 files on this directory.
[2]User Archive directories that were created (or had no user data) after January 14, 2020. Settings other than permissions are not applicable because directories are root-owned and contain no user files.


Moderate Enhanced projects do not have HPSS storage

User Home Directories (NFS)

The environment variable $HOME will always point to your current home directory. It is recommended, where possible, that you use this variable to reference your home directory. In cases in which using $HOME is not feasible, it is recommended that you use /ccs/home/$USER.

Users should note that since this is an NFS-mounted filesystem, its performance will not be as high as other filesystems.

User Home Quotas

Quotas are enforced on user home directories. To request an increased quota, contact the OLCF User Assistance Center. To view your current quota and usage, use the quota command:

$ quota -Qs
Disk quotas for user usrid (uid 12345):
     Filesystem  blocks   quota   limit   grace   files   quota   limit   grace
                  4858M   5000M   5000M           29379   4295m   4295m


Moderate enhanced projects have home directores located in GPFS. There is no enforced quota, but it is recommended that users not exceed 50 TB. These home directories are subject to the 90 day purge

User Home Permissions

The default permissions for user home directories are 0750 (full access to the user, read and execute for the group). Users have the ability to change permissions on their home directories, although it is recommended that permissions be set to as restrictive as possible (without interfering with your work).


Moderate enhanced projects have home directory permissions set to 0700 and are automatically reset to that if changed by the user.

User Home Backups


There are no backups for moderate enhanced project home directories.

If you accidentally delete files from your home directory (/ccs/home/$USER), you may be able to retrieve them. Online backups are performed at regular intervals. Hourly backups for the past 24 hours, daily backups for the last 7 days, and once-weekly backups are available. It is possible that the deleted files are available in one of those backups. The backup directories are named hourly.*, daily.*, and weekly.* where * is the date/time stamp of backup creation. For example, hourly.2020-01-01-0905 is an hourly backup made on January 1st, 2020 at 9:05 AM.

The backups are accessed via the .snapshot subdirectory. Note that ls alone (or even ls -a) will not show the .snapshot subdirectory exists, though ls .snapshot will show its contents. The .snapshot feature is available in any subdirectory of your home directory and will show the online backups available for that subdirectory.

To retrieve a backup, simply copy it into your desired destination with the cp command.

User Website Directory

Users interested in sharing files publicly via the World Wide Web can request a user website directory be created for their account. User website directories (~/www) have a 5GB storage quota and allow access to files at (where user is your userid). If you are interested in having a user website directory created, please contact the User Assistance Center at

User Archive Directories (HPSS)


Use of User Archive areas for data storage is deprecated as of January 14, 2020. The user archive area for any user account created after that date (or for any user archive directory that is empty of user files after that date) will contain only symlinks to the top-level directories for each of the user’s projects on HPSS. Users with existing data in a User Archive directory are encouraged to move that data to an appropriate project-based directory as soon as possible.

The information below is simply for reference for those users with existing data in User Archive directories.

The High Performance Storage System (HPSS) at the OLCF provides longer-term storage for the large amounts of data created on the OLCF compute systems. The mass storage facility consists of tape and disk storage components, servers, and the HPSS software. After data is uploaded, it persists on disk for some period of time. The length of its life on disk is determined by how full the disk caches become. When data is migrated to tape, it is done so in a first-in, first-out fashion.

User archive areas on HPSS are intended for storage of data not immediately needed in either User Home directories (NFS) or User Work directories (GPFS). User Archive directories should not be used to store project-related data. Rather, Project Archive directories should be used for project data.

User archive directories are located at /home/$USER.

User Archive Access

Each OLCF user receives an HPSS account automatically. Users can transfer data to HPSS from any OLCF system using the HSI or HTAR utilities. For more information on using HSI or HTAR, see the HPSS Data Archival System .

User Archive Accounting

Each file and directory on HPSS is associated with an HPSS storage allocation. For information on HPSS storage allocations, please visit the Data Policies section.

For information on usage and best practices for HPSS, please see the HPSS Data Archival System documentation.