Storage

All MCSR systems share home directories. Home directories are stored on a network-attached storage appliance. It is attached to MCSR systems via Infiniband.

In the past, all MCSR users had a /ptmp directory in addition to their home directory for large files. During a 2017 upgrade these directories were combined. Existing users had their ptmp directories copied into their home directory and a symbolic link was setup in /ptmp so that existing scripts would continue to work. Users created since the upgrade have no trace of a ptmp directory.

All systems also share a /scratch area for large temporary files. Each user has their own directory inside the /scratch area. This area is stored on the same device as the home directories. Users should cleanup after themselves in their PBS scripts. This area is NOT backed up, and is subject to being purged as needed.

All nodes have /tmp directories for temporary files, but they vary greatly in size. Most are backed by hard drives. The exception is Maple’s newer nodes, which are diskless and use a RAM disk for /tmp. They are very fast, but limited to 12GB. In most cases, writing to /scratch is faster than writing to /tmp. The primary exception is some computational chemistry software that writes very large intermediate files.

Mostly for historical reasons, our default settings allow users to see each other’s files. We have considered changing this in the past and have decided against it. If this is an issue for you, you should change the permissions on your existing files and change your default umask so that new files will be created with stricter permissions. Contact MCSR staff for assistance.