File storage and I/O
Franklin File Systems
The Franklin system has 4 different file systems mounted which provide different levels of disk storage, I/O performance and file permanence. The table below describes the various Franklin file systems
|File System||Home||Local Scratch||Project|
|No environment variable
||GPFS global file system mounted on all NERSC systems.|
|Peak Performance||Low, ~100 MB/sec||17 GB/sec for each||40 GB/sec|
|Purged?||No||Yes, files older than 12 weeks are purged.||No|
Franklin is configured with two distinct scratch file systems named /scratch and /scratch2. Each user therefore has access to two scratch directories, which should always be referenced using the environment variables $SCRATCH and $SCRATCH2. Both file systems are available from all nodes, and are tuned for high performance. See Optinizing I/O Performance on Lustre File Systems. Users may run out of either scratch file system, but are encouraged to choose one or the other for their primary work.
The contents of $SCRATCH and $SCRATCH2 are deleted ("purged") if the files are older (defined by last access time) than 12 weeks. Please back up your important files frequently to HPSS.
There is a single (large) quota (space and inode) for each user that applies to the combined contents of $SCRATCH and $SCRATCH2. If your combined usage of $SCRATCH and $SCRATCH2 exceeds your quota, you will not be able to submit batch jobs until you reduce your combined usage.
The "myquota" command (with no options) will display a user's current usage and quota. NERSC sometimes grants temporary quota increases for legitimate purposes. To apply for such an increase, please see Disk Quota Increase Form.
Do Not Use /tmp Explicitly
WARNING: Do not attempt to explicitly use a file system named /tmp. Your job may fail or be deleted if it writes to /tmp. Some software tools (editors, compilers, etc.) use the location specified by the $TMPDIR environment variable to store temporary files. Additionally, Fortran codes which open files with status="scratch" will write those files into $TMPDIR. On many Unix systems, $TMPDIR is set to /tmp. NERSC has set $TMPDIR to be $SCRATCH. Please do not redefine $TMPDIR!