NERSCPowering Scientific Discovery Since 1974

Other File Systems

User Home Directories

Your home directory is located at /home/login-name.  Home directories are mounted to all PDSF nodes, are regularly backed up, and currently have 5 GB disk quotas. The "myquota" command shows quotas and usage in terms of space (GB) and inodes (the number of files and directories). Use the -M option of myquota to display in MB instead of GB. See also Checking quotas for more about myquota.

Home directories are backed up as insurance against catastrophic file system failure. Individual files or directories can not be restored so users must back up important files to HPSS, to local storage, or elsewhere. Please back up all your important files on a regular basis.

Local Scratch Directories

These areas are designated as /scratch on each PDSF node. The disks are not cross mounted between nodes in the PDSF system.

The scratch areas currently are partitions (~10 GB for batch nodes and 658 GB for interactive nodes) useful for single node processes with significant I/O requirments which can be directed to locally stored data files. Files in these areas are not backed up and should be moved to more stable storage areas after use.

We have the following policy for scratch cleanup on the interactive nodes:

  • If the partition is greater than 95% full, delete all files except those of running jobs.

On batch nodes only files belonging to the currently running jobs are kept. Users can request their batch jobs be sent to nodes with a specific amount of scratch space available by specifying a scratch resource requirement (see Submitting PDSF Jobs for a full list of options).

Use of /common

The /common file system is a special file system primarily for software installations. It is optimized for the reading of files and should be treated as a read-only file system as much as possible. It is NOT to be used for general purposes such as writing log files, batch job output files, etc.

Project

While technically not part of PDSF, the NERSC Global Project file system is available from all PDSF nodes as /project. You can write under your group's directory which is located at /project/projectdir/<groupname>.   Note that prjquota is used instead of myquota on /project - see Checking quotas for more information. See also the NERSC webpages about Science gateways.

You can host webpages on /project. See Hosting Webpages for more information.

Global Scratch

The NERSC Global Scratch file system is available on the newer PDSF nodes as $GSCRATCH. The global scratch file system is intended for temporary storage of files and is periodically purged. You can view your global scratch quota with the myquota command.

ALICE XRootD Servers

XRootD gives high performance, scalable fault tolerant access to the ALICE data repositories. There are 10 XRootD servers. They are Dell PowerEdge R710 servers each configured into 8 filesystems with a Dell MD1200 disk vault with 72 TB of raided storage space each for a total of 720 TB storage.