There are different ways to setup the MCA parameters in Sensys. Following are methods to setup MCA parameters and its order of precedence.

Each Sensys application command line supports the following command line options:

<orcmapp> –-omca <param_name> <value>

The command line options override the default options in Sensys takes precedence over other methods of setting up MCA parameters.

Using Sensys MCA environment variables MCA parameter can be setup for all Sensys tools in this node. The environment setup can be overridden using the next command line parameter:

export ORCM_MCA_<mca_param_name>=<value>

Under each node type setup MCA parameters using the MCA xml tag. These are default settings and takes precedence over other methods of setting up MCA parameters. This is applicable for all tools and daemons using this orcm-site.xml for startup. These are specified in key=value format.

Use the openmpi-mca-params.conf file to setup the global default MCA parameters. This method is overridden using the above methods in the order or precedence. We need to protect the visibility of certain MCA parameters such as the database and BMC's username and passwords as these are privileged information. Hence it's recommended to have constricted privileges on this file. System-admin should make sure that the permissions on the openmpi-mca-params.conf file should be set to 0600 to secure the file contents. This can be done using the following command:

chmod 0600 openmpi-mca-params.conf

Some MCA parameters are required and they have programming defaults hardcoded in the code. This default values can be overridden using the above methods. To get a list of all possible MCA parameters, run the following command: (orcm-info --help for details)

$ orcm-info  --param  all  all

To set the parameter in any orcm program (including orcmd and opal_db) use the following syntax:

$ <orcmprog> --omca  parameter1-name  parameter1-value  \
                [--omca parameter2_name parameter2_value] ...

For example:

% orcmd --omca sensor_base_sample_rate=5 \
             --omca sensor_base_log_samples=1