Permanent and Temporary Files
Home Directory
Only files you need for a longer time period should reside in your home directory. The home directories are in /bwfs/home/hd. Physically, the data are located on the bwGRiD storage system in Mannheim. The homes on the login server are identical with the homes on the compute nodes. So, you should use exactly the same file name and directory name on the login server and on the compute nodes to read or manipulate a file.
There is no backup for the home directory. The disk space per user is limited to 100 GB.
Scratch Directory
Temporary files can be stored in workspaces located in the scratch directory /bwfs/scratch. A new workspace is created with the command
ws_allocate workspacename days
The number given for days determines the life-time of the workspace in days. The maximum value for days is 60. The command
ws_extend workspacename days
resets the life-time of an existing workspace to the original value (command without days) or sets the life-time to a different value (command with days). If the life-time of a workspace expires, it is deleted automatically. With
ws_release workspacename
you can delete a workspace before expiration.
Other important workspace commands are
ws_list
which shows the location and the remaining life-time of all your workspaces and
ws_find workspacename
which returns the path to a particular workspace.
The data in the scratch directory are located on the bwGRiD storage system in Heidelberg. Just like your home directory, the workspaces on the login server are identical with those on the compute nodes. It is recommended to start jobs from workspaces and to store large data sets there. The disk space in workspaces is not limited.
Directory /tmp
Each compute node has its own /tmp with 120 GB disk space on the internal hard drive, which can be used for temporary files during job execution. The data in these directories are deleted as soon as the job is finished.
The /tmp directory on the login server should not be used.
Overview
| Directory | Access | Purpose | Total disk space | Backup |
/bwfs/home/hd |
from the login server and all compute nodes | for permanent data up to 100 GB | 32 TB | no |
/bwfs/scratch |
from the login server and all compute nodes | for data in workspaces | 32 TB | no |
/tmp |
only from the respective compute node | for data during job execution | 120 GB | no |
Important note
The bwGRiD storage systems are equipped with the parallel filesystem Lustre which is optimized for fast file access. This feature requires a higher complexity of the storage system and leads to a reduced stability at the same time. Failures should be expected. Therefore we recommend to analyze results as soon as possible and to save important data elsewhere.