Fast scratch folder (/disco2fs/username)
========================================

About
-----

.. important:: The purpose of the ``/disco2fs`` file system is to give the researcher a fast storage location that can store files used by the simulation software for parallel read/write operations. That storage location has a limited capacity (27 TB in total) and its use is limited. Therefore, it is not advisable to use that location as a permanent storage and archive. Only live data created or needed by the simulations can be hosted with it. After the data processing is complete, the piled files must be either deleted or moved to another storage location (let us say, the personal or per-project storage location, see :doc:`scratchfolder` and :doc:`storage_moving_files_overquota`).

Your fast scratch folder is located at ``/disco2fs/username``, where ``username`` is your Discoverer HPC username (the account name). Physically, that folder lives on `Luster file system`_, which is able to handle high I/O loads. Your running jobs should be configured to write there their output files.

.. warning:: You MUST NOT use ``/disco2fs/username`` as an archive storage folder for data that isn't being used or processed.

Size/Quota
----------

.. note:: 50 GB of personal disk space (quota) on /disco2fs file system and up to 1300000 files and folders.

Each active user, regardless of the number of projects he or she contributes to, receives **50 GB of personal disk space (quota) on /disco2fs file system,** unless another number is negotiated (which is rare due to the limited total storage capacity of ``/disco2fs`` - only 27 TiB). The folder ``/disco2fs/usename`` cannot contain more than 1300000 files and folders and the utilization of the personal user disk space on ``/disco2fs`` is estimated as the sum of the size of all files on that file system that belong to the primary POSIX group of the user (``username``).

To check the current user disc space utilization on ``/disco2fs``, execute the following command line on the login node (replace ``username`` with your actual username):

.. code-block:: bash

 lfs quota -g username /disco2fs

*on Discoverer HPC, the name of the primary POSIX group always coincides with the username*

The document :doc:`calculating_the_disk_usage_basics` explains how to interpret the numeric information provided by the quota check.

Data retention policy
---------------------

The files stored in ``/disco2fs/username`` are retained for 45 days after the user account has been deactivated. Afterwards, they undergo a wipe out. Discoverer HPC reserves the right to modify and augment the aforementioned policy, upon which the user shall be provided with an early warning.


Help
----

If you experience issues with accessing your scratch folder and the content stored there, contact the Discoverer HPC support team (see :doc:`help`).

.. _`Luster file system`: https://en.wikipedia.org/wiki/Lustre_(file_system)