Project filesystem

The project file system is a global file system available on all NERSC computational systems. It allows sharing of data between users, systems, and the "outside world".


Every MPP repository has an associated project directory and unix group. Project directories are created in /project/projectdirs. All members of the project have access through their membership in the unix group.

Occasionally there are cases where the above model is too limiting. For example:

  • large projects with multiple MPP repositories
  • long-term projects which outlive specific MPP repositories

In these cases, a project directory administrator may request the creation of a "designer" project directory with a specific name. This will result in the creation of a new Unix group with that name, consisting solely of the project directory administrator, followed by the creation of the project directory itself. The project directory administrator must then use NIM to add users to the newly-created Unix group.


If you are a PI or a PI Proxy, you can request a designer project directory in NIM.

  1. Search for the MPP repository name you wish this designer project directory to be attached to.
  2. Scroll to the bottom of the "Project Information" tab and you will see a link that says "Request a custom project directory".



See quotas for detailed information about inode, space quotas, and file system purge policies.


The system has a peak aggregate bandwidth of 130 GB/sec bandwidth for streaming I/O. While user applications that depend on high-bandwidth for streaming large files can use the Project file system, it is recommended to use Cori scratch or the Burst Buffer instead.


All NERSC users should backup important files on a regular basis. Ultimately, it is the user's responsibility to prevent data loss. However, NERSC provides some mechanisms in protecting against data loss.


Project directories use a snapshot capability to provide users a seven-day history of their project directories. Every directory and sub-directory in a project directory contains a ".snapshots" entry.

  • .snapshots is invisible to ls, ls -a, find and similar commands
  • Contents are visible through ls -F .snapshots
  • Can be browsed normally after cd .snapshots
  • Files cannot be created, deleted or edited in snapshots
  • Files can only be copied out of a snapshot


Project directories will remain in existence as long as the owning project is active. Projects typically "end" at the end of a NERSC Allocation Year. This happens when the PI chooses not to renew the project, or DOE chooses not to provide an allocation for a renewal request. In either case, the following steps will occur following the termination of the project:

  1. -365 days - The start of the new Allocation Year and no Project renewal

    The data in the project directory will remain available on the project file system until the start of the next Allocation Year. Archival process begins.

  2. +0 days - The start of the following Allocation Year

    Users notified that the affected project directory will be archived, and then removed from the file system in 90 days.

  3. +30 days

    The project directory will become read-only.

  4. +60 days

    The full pathname to the project directory will be modified. Automated scripts will likely fail.

  5. +90 days

    User access to the directory will be terminated. The directory will then be archived in HPSS, under ownership of the PI, and subsequently removed from the file system.