.. include:: system.rst

.. _jureca_faq:

FAQ
===

Here you can find a list of frequently asked questions about |SYSTEM_NAME|:

FAQ about |SYSTEM_NAME|
+++++++++++++++++++++++

How can Intel MPI be tuned for the JURECA InfiniBand network?
-------------------------------------------------------------
By default, Intel MPI uses uDAPL (Direct Access Programming Library) for inter-node MPI communication via
the InfiniBand fabric. In many cases better performance can be achieved with the low-level OFED ``libibverbs``
library. In order to select the ``ofa`` fabric for Intel MPI inter-node communication, export the following
environment variable in your job script or ``salloc`` session:

.. code-block::

   export I_MPI_FABRIC=shm:ofa

Error Messages on |SYSTEM_NAME|
+++++++++++++++++++++++++++++++

What does the error message "vsetenv ... failed" mean?
------------------------------------------------------
The warning message

.. code-block::

   Note: Max supported value for env var is 4095
   vsetenv ... failed

is generated by the InfiniBand driver userspace library when an environment variable exceeds the limit of 4095
characters. This warning has no effect on the running job and can safely be ignored until a fix is available.

.. include:: ../shared/faq.rst

FAQ about Data Management
+++++++++++++++++++++++++

.. include:: ../shared/faq-just.rst