Filesystems

As soon as you have access to ZIH systems, you have to manage your data. Several filesystems are available. Each filesystem serves for special purpose according to their respective capacity, performance and permanence.

We differentiate between permanent filesystems and working filesystems:

• The permanent filesystems, i.e. /home and /projects, are meant to hold your source code, configuration files, and other permanent data.
• The working filesystems, i.e, horse, walrus, etc., are designed as scratch filesystems holding your working and temporary data, e.g., input and output of your compute jobs.

Recommendations for Filesystem Usage

To work as efficient as possible, consider the following points

• Save source code etc. in /home or /projects
• Store checkpoints and other temporary data in workspaces on horse
• Compilation should be executed in /dev/shm or /tmp

Getting high I/O-bandwidth

• Use many clients
• Use many processes (writing in the same file at the same time is possible)
• Use large I/O transfer blocks
• Avoid reading many small files. Use data container e. g. ratarmount to bundle small files into one

Cheat Sheet for Debugging Filesystem Issues

Users can select from the following commands to get some idea about their data.

General

For the first view, you can use the command df.

marie@login$ df

Alternatively, you can use the command findmnt, which is also able to report space usage by adding the parameter -D:

marie@login$ findmnt -D

Optionally, you can use the parameter -t to specify the filesystem type or the parameter -o to alter the output.

Important

Do not use the du-command for this purpose. It is able to cause issues for other users, while reading data from the filesystem.