Storage Systems

Modified

March 20, 2026

Abstract

This section gives an overview over storage systems connected to the compute cluster infrastructure. This includes CVMFS - used to distribute software, and the Lustre shared storage used to hold input and output data for scientific 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 login- and submit-nodes, and not on the cluster compute 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.
Scratch	`/scratch/`	Central volatile scratch storage for software development. Space is limited by quota (per group). No backup. Read-write access through nodes in the `work` partition (read-only on submit and batch worker nodes).
Temporary Storage	`/tmp/`	Each compute node provides local volatile scratch storage in the `/tmp` directory. Use this storage for intermediate data during job execution only.

Warning

Both /scratch/ and /tmp/ are volatile storage, and therefore no backup in any form. Files in /tmp are cleaned automatically based on age and capacity.

Do not rely on these locations for persistent data.

Home Directory

No home-directory on Compute nodes!

Network home-directories /u/$USER/ are only accessible on interactive nodes like the submit nodes. This means users can not start an application from their home-directory when a job is submitted to the cluster. Output from a job can not be stored in the home-directory.

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

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

--- title: Storage Systems date-modified: 2026/03/20 abstract: > This section gives an overview over storage systems connected to the compute cluster infrastructure. This includes CVMFS - used to distribute software, and the Lustre shared storage used to hold input and output data for scientific applications. --- ## Overview The compute cluster is connected to multiple storage facilities listed in the following table: Name | Path | Description ------------------------|-----------------|------------------------- Home-directory | `/u/$USER/` | The private user home-directories are available on all [login-][D8BGg] and [submit-nodes][rm5Tt], and not on the cluster compute nodes. More details are described in the [home-directory](#home-directory) section below. CVMFS | `/cvmfs/` | Experiment and working group specific software is available via [CVMFS][D2jRt]. Shared Storage (Lustre) | `/lustre/` | The Lustre parallel file-system provides shared storage to all computing nodes. Find the documentation in the [Shared Storage][3z3Ps] section. It is the primary storage for permanent data. Scratch | `/scratch/` | Central volatile scratch storage for software development. Space is limited by quota (per group). No backup. Read-write access through nodes in the `work` partition (read-only on submit and batch worker nodes). Temporary Storage | `/tmp/` | Each compute node provides local volatile scratch storage in the `/tmp` directory. Use this storage for intermediate data during job execution only. ::: {.callout-warning} Both `/scratch/` and `/tmp/` are **volatile** storage, and therefore no backup in any form. Files in `/tmp` are cleaned automatically based on age and capacity. **Do not rely on these locations for persistent data.** ::: [rm5Tt]: access/submit-nodes.md [D8BGg]: access/submit-nodes.md#login-nodes [D2jRt]: storage/cvmfs.md [3z3Ps]: storage/lustre.md ## Home Directory **No home-directory on Compute nodes!** Network home-directories `/u/$USER/` are only accessible on interactive nodes like the [submit nodes][rm5Tt]. This means users can not start an application from their home-directory when a job is submitted to the cluster. Output from a job can not be stored in the home-directory. Network home-directories are provided by NFS [^nfs] 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. [^nfs]: Network File System, Wikipedia <https://en.wikipedia.org/wiki/Network_File_System> 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][uqkJi] to your local computer. [uqkJi]: access/mount-cluster-storage.html