.. _basics:


Basics
====================

Before diving into the different functionalities of **GRAVITON** and the usage of the job scheduler (**SLURM**), it is important to understand some basic aspects of the system that all users should be familiar with.

Directories
------------

Each user has a unique, personal, and non-transferable home directory located at:

.. raw:: html

    <pre class="cuadro_solarizado"><code><strong><span>[username@grui01 ~]$ </span></strong> /lhome/ific/u/username</code></pre>

Here, `username` corresponds to your actual user ID. These personal directories are organized in subfolders based on the first letter of the username. For example, a user with the name `username`, which starts with a `u`, will have a home directory under `/lhome/ific/u/`.

In addition to personal directories, **GLUON project directories** are also available and synchronized on GRAVITON. If you are also a GLUON user, you will have write access to the corresponding group directories.

These shared directories can be found at:

.. raw:: html

    <pre class="cuadro_solarizado"><code><strong><span>[username@grui01 ~]$ </span></strong> /lustre/ific.uv.es/prj/gl</code></pre>

Within this path, each research group has its own subdirectory. Most GRAVITON users belong to one or both of the **SOM subgroups** within GLUON: `mosayco` and `somlat`.

To check your group memberships, you can use the `id` command:

.. raw:: html

    <pre class="cuadro_solarizado"><code><strong><span>[username@grui01 ~]$ </span></strong> id</code></pre>




Useful Commands
----------------

This section describes some useful commands available for interacting with GRAVITON.


Graviton Quota
.............

``grquota`` is a script to retrieve user quota information in the GRAVITON system.

**Usage:**

.. code-block:: bash

    [username@glui01 ~]$ grquota

**Description:**

- Retrieves the quota for the user in `/lhome/ific/`.
- Lists the GLUON groups the user belongs to and checks if they have a Lustre project directory.
- If the group has a Lustre directory, it displays its quota.

**Example Output:**

.. code-block:: text

    --------------------------------------------------------
    Disk quotas for user username (uid 12345):
          Filesystem  space   quota   limit   grace   files   quota   limit   grace
    /lhome/ific/u     10G     50G     60G     -       1000    5000    6000    -
    --------------------------------------------------------
    Disk quotas for project 6010:
          Filesystem  space   quota   limit   grace   files   quota   limit   grace
    /lustre/ific.uv.es/prj/gl     500G    1T      1.2T    -       50000   100000  120000  -
    --------------------------------------------------------


Graviton Status
...............

``grstatus`` is a monitoring script used to check the current status of the GRAVITON nodes.

**Usage:**

.. code-block:: bash

   [username@grui01 ~]$ grstatus

**Description:**

- Displays the number of allocated and total CPUs per node.
- Shows the allocated and total memory for each node in the GRAVITON infrastructure.
- The information is retrieved directly from SLURM metrics using `scontrol`, ensuring accurate and up-to-date status reporting.

This tool is particularly useful for users and administrators to quickly assess the system load and available resources across the cluster.


**Example Output:**

.. code-block:: text

   NODE         ALLOC_CPU  TOTAL_CPU  ALLOC_MEM  REAL_MEM
   grwn01       0          56         0          245000
   grwn02       0          56         0          245000
   grwn03       0          56         0          245000
   grwn04       0          56         0          245000
   grwn05       0          56         0          245000