Storage Systems

Abstract

This section overviews storage systems connected to the compute cluster infrastucture. This include CVMFS used to distiibute software, and the Lustre shared storage used to hold inpout and output data for scientifdic applications.

Overview

The compute cluster is connected to multiple storage facilities listed in the following table:

Name	Path	Description
Home-directory	/u/$USER/	The private user home-directories are available on all interactive login- and submit-nodes. More details are described in the home-directory section below.
CVMFS	/cvmfs/	Experiment and working group specific software is available via CVMFS.
Shared Storage (Lustre)	/lustre/	The Lustre parallel file-system provides shared storage to all computing nodes. Find the documentation in the Shared Storage section. It is the primary storage for permanent data.
Temporary Storage	/tmp/	Each compute node provides local volatile scratch storage in the /tmp directory. The temporary storage is cleaned automatically depending on the age of files and the overall capacity. Use this storage for intermediate data which is only available during a jobs execution.

Home Directory

Network home-directories /u/$USER/ are only accessible on a submit node and not on the compute nodes.

Network home-directories are provided by NFS ¹ servers and therefore have limitations in performance when accessed from many nodes at once. The execution nodes in the cluster do not mount the home-directories in order to prevent the GSI NFS servers from being overloaded by user access.

To improve the work effectiveness on the cluster, e.g. using a local text editor or modifying files directly, it is recommended to mount your GSI network home-directory to your local computer.

Footnotes

1. Network File System, Wikipedia
   https://en.wikipedia.org/wiki/Network_File_System