Skip to content

Storage systems


Apocrita has over a petabyte of IBM Spectrum Scale (formerly called GPFS) storage. This is a high-performance clustered file system which provides concurrent high-speed file access to your data.

It is widely used in HPC both commercially and in academia. The storage system is connected to the QMUL Enterprise backup solution (TSM) to provide a high level of data resilience.

Home directories


All users have a home directory mounted under /data/home (e.g. /data/home/abc123). This is networked storage, is accessible from all nodes in the cluster and is backed up nightly. This space is deliberately small and limited to 60GB per user (12GB for taught students). Avoid using this space as a destination for data generated by cluster jobs, as home directories fill up quickly and exceeding your quota will cause your jobs to fail.


Scratch space is used for temporary storage of files.

Lab/Project storage space

Users may have project or lab storage allocated to them, the location of this storage is specific to your group. Each research project or lab can have 1TB of free shared space for this. If you do not have this set up for your group, please complete our storage request form. If the lab share already exists and you require access to it, please send an email to and also include your PI in CC.

If you or your group requires more than this, Additional Storage space can be purchased.

In addition to data storage for users, Apocrita also stores some widely used public datasets.

Local disk space on nodes - $TMPDIR

There is temporary space available on the nodes that can be used when you submit a job to the cluster. The size of this storage per node type is listed on the individual node types page.

As this storage is physically located on the nodes, it cannot be shared between them, but it might provide better performance for I/O intensive tasks than networked storage. Examples are on the Using $TMPDIR page.

Additional storage

Additional backed-up storage is available for purchase at £150 per 1TB per annum. This can be arranged by submitting an email to and including an Agresso budget code.