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Data storage options

On LUMI you have access to network file system storage based on the LUMI-P and LUMI-F hardware partitions. At a later point, object storage based on LUMI-O will also become available. The use of storage is billed according to the billing policy.

Where to store data?

Each user has a home directory ($HOME) that can contain up to 20 GB of data. It is intended to store user configuration files and personal data. The user home directory is purged once the user account expires.

Persistent storage intended to share data amongst the members of a project. You can see this disk area as the project home directory. Typically, this space is used to share applications and libraries compiled for the project. The project persistent storage is located at /project/project_<project-number>. The project persistent directory is purged once the project expires.

Temporary storage for input, output, or checkpoint data of your application. When running jobs on LUMI, this is the main storage you should use for your disk I/O needs.

You are not supposed to use the scratch space as long-term storage. The scratch file system is a temporary storage space. Files that have not been accessed will be purged after 90 days.

A high performance variant of project scratch. Use this when running jobs on LUMI that need very fast disk I/O operations. Note the difference in billing of the project scratch and project fast as detailed on the billing page.

The project flash space is only meant for very short term file storage. Files that have not been accessed will be purged after 30 days.

LUMI network file system disk storage areas

On LUMI there are several network based disk storage areas. An overview is provided in the tables below. Please familiarize yourself with the characteristics of the hardware partitions before using the different storage areas.

Path Intended use Hardware partition used
User
home
/users/<username> User home directory for
personal and configuration files
LUMI-P
Project
persistent
/project/<project> Project home directory for
shared project files
LUMI-P
Project
scratch
/scratch/<project> Temporary storage for
input, output or checkpoint data
LUMI-P
Project
flash
/flash/<project> High performance temporary
storage for input and output data
LUMI-F
Quota Max files Expandable Backup Retention
User
home
20 GB 100k No Yes User lifetime
Project
persistent
50 GB 100k Yes,
up to 500GB
No Project lifetime
Project
scratch
50 TB 2000k Yes,
up to 500TB
No 90 days
Project
fast
2 TB 1000k Yes,
up to 100TB
No 30 days

Note that, except for the user home directory, data storage is allocated per project. When a storage space is marked as expandable, it means that you can request more space if needed. Please contact the User Support Team to request more storage space.

Data retention policies are not active

Automatic cleaning of project scratch and fast storage is not active at the moment. Please remove the files that are no longer needed by your project on a regular basis.

Don't circumvent the retention policy

Deliberately modifying file access times to bypass the retention policy is prohibited. It's an anti-social behavior that may impact other users negatively.

About the number of files quota

For reasons related to performance, we are particularly attentive to the number of files present on the parallel file system. A lot of small files negatively impact all users by stressing the file system metadata servers. Therefore, any requests to increase the number of files quota will be evaluated carefully by the User Support Team and must be fully justified to be granted.

Examples of requests that will be rejected include:

  • You are installing a lot of small files, e.g. using Conda. Please use a container or the container wrapper tool instead.
  • The compilation of your application is generating too many files for your home or project directory: you should compile your application from the scratch and then install it in your home or project directory. Exceptions can be made if you are developing an application on LUMI and you want to keep the source and object files in the long term.

In general, applications that generate a lot of small files per process are not well suited for LUMI. If you are the developer of such application, you should consider tools like HDF5 or SIONlib.

You can check the memory and file usage quotas of your projects with the following commands:

$ module load lumi-workspaces
$ lumi-workspaces

Temporary storage on compute nodes

The /tmp directory on the compute nodes resides in memory. The memory used for /tmp is included in the job memory allocation. If you use /tmp, you must allocate memory for it in order to avoid running out of memory.