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Cori has one scratch file system named /global/cscratch1 with 30 PB disk space and >700 GB/sec IO bandwidth. Cori scratch is a Lustre filesystem designed for high performance temporary storage of large files. It contains 10000+ disks and 248 I/O servers (OSSs/OSTs).

The /global/cscratch1 file system should always be referenced using the environment variable $SCRATCH (which expands to /global/cscratch1/sd/YourUserName). The scratch file system is available from all nodes (login, MOM, and compute nodes) and is tuned for high performance. We recommend that you run your jobs, especially data intensive ones, from the burst buffer or the scratch file system.

All users have 20 TB of quota for the scratch file system. If your $SCRATCH usage exceeds your quota, you will not be able to submit batch jobs until you reduce your usage. The batch job submit filter checks the usage of /global/cscratch1.

The myquota command will display your current usage and quota. NERSC sometimes grants temporary quota increases for legitimate purposes. To apply for such an increase, please use the Disk Quota Increase Form.

The scratch file system is subject to purging. Files in your $SCRATCH directory that are older than 12 weeks (defined by last access time) are removed. Please make sure to back up your important files (e.g. to HPSS). Instructions for HPSS are here.

To restore deleted or purged files, please refer to Backup/Restore on Home directory or Projects directory.