.. _change-the-default-coredump-configuration-51ff4ce0c9ae:

=========================================
Change the Default Coredump Configuration
=========================================

You  can change the default core dump configuration used to create *core*
files. These are images of the system's working memory used to debug crashes or
abnormal exits.

.. rubric:: |context|

The editable parameters and their defaults are as follows:

``ProcessSizeMax``
   The maximum size of cores that will be processed.

   Default: 2G

   Minimum: 0

``ExternalSizeMax``
   The maximum size of cores to be saved.

   Default: 2G

   Minimum: 0

``MaxUse``
   Sets a maximum diskspace usage by cores.

   Default: *unset*

``KeepFree``
  Sets the minimum amount of disk space to keep free when saving cores.

  Default: 1G

  Minimum: 1G

Maximum values for each configurable coredump parameter depends on system
capacity.

The parameters accept integer/float values followed by a letter representing
the unit of measurement.

* ``B`` = Bytes
* ``K`` = Kilobytes
* ``M`` = Megabytes
* ``G`` = Gigabytes
* ``T`` = Terabytes
* ``P`` = Petabytes
* ``E`` = Exabytes

The value 0 (zero) is accepted by parameters ``ProcessSizeMax``,
``ExternalSizeMax`` and ``MaxUse``.

.. Note::
    Other, non-configurable, parameters are:

    * ``Storage`` = external
    * ``Compress`` = yes
    * ``JournalSizeMax`` = 767M


For more information on these values, see
https://man7.org/linux/man-pages/man5/coredump.conf.5.html


.. rubric:: |prereq|

Ensure that you have sufficient storage available on the host's ``log``
filesystem. See :ref:`resizing-filesystems-on-a-host` for more information
about adjusting it's size.

The *log* (``/var/log``) filesystem size is defaulted for standard platform
operation.  If there is an expected usage increase due to the application core
dump files, it should be increased proportionally to the core dump size and the
expected number of core dumps that need to be retained.  The core dump storage
limits can be explicitly configured using the system ``max_use`` parameter
settings that aligns to the core dump storage and retention requirements.

For example:

Filesystem Setting:

``8G (default) + 10G (core dump size x retention count - 5G x 2) = 18G``

Core Dump Setting:

``max_use = 10G (core dump size x retention count - 5G x 2)``


.. rubric:: |eg|

When you configure a parameter, it will be replicated to the ``coredump.conf``
file of all existing nodes (controllers, workers, storages).

*  To add a coredump service parameter:

   .. code-block:: none

      ~(keystone_admin)]$ system service-parameter-add platform coredump <parameter>=<value>

*  To modify an existing coredump service parameter:

   .. code-block::

      ~(keystone_admin)]$ system service-parameter-modify platform coredump <parameter>=<value>

*  To delete an existing coredump service parameter:

   .. code-block::

      ~(keystone_admin)]$ system service-parameter-delete <uuid>

   .. note::

      When a parameter is deleted, its value will reset to the default.


Where <parameter> can be one of:

*  ``process_size_max``
*  ``external_size_max``
*  ``max_use``
*  ``keep_free``

The following example sets ``ExternalSizeMax`` to 3 gigabytes.

.. code-block:: none

   ~(keystone_admin)]$ system service-parameter-add platform coredump external_size_max=3G

.. note::

   Configuring a parameter raises the 250.001 *controller-0 Configuration
   is out-of-date* alarm. A lock/unlock is required to clear it. For more
   information, see :ref:`locking-a-host-using-the-cli` and
   :ref:`unlocking-a-host-using-the-cli`.