Manage scheduling performance

The LSB_MAX_JOB_DISPATCH_PER_SESSION parameter in the lsf.conf file, and the MAX_SBD_CONNS parameter in the lsb.params file are set automatically during mbatchd daemon startup, to enable the fastest possible job dispatch.

The LSB_MAX_JOB_DISPATCH_PER_SESSION value is the maximum number of job decisions that the mbschd daemon can make during one job scheduling session. The default value is LSB_MAX_JOB_DISPATCH_PER_SESSION = Min (MAX(300, Total CPUs), 3000).

Sets the maximum number of open file connections between the mbatchd and sbatchd daemons.

The MAX_SBD_CONNS setting is the maximum number of open file connections between the mbatchd and sbatchd daemons. The default value is MAX_SBD_CONNS = 2 * number_of_hosts + 300. This formula does not provide the exact number of sbatchd connections because it also calculates the lost and found hosts. Therefore, the calculated number of connections might be a few more than this theoretical number.
Tip: If you enabled the IBM® Spectrum LSF resource connector, there can be many LSF server nodes joining and leaving from the LSF clusters frequently. In this case, rather than use the default value for MAX_SBD_CONNS, define a more reasonable value. For example, set it as MAX_SBD_CONNS = 2 * maximum_number_of_hosts + 300.

The LSB_MAX_JOB_DISPATCH_PER_SESSION and MAX_SBD_CONNS settings affect the number of file descriptors. Although the system sets the default values for both parameters automatically when the mbatchd daemon starts, you can adjust them manually.

To decrease the load on the management host LIM, you should not to configure the management host as the first host for the LSF_SERVER_HOSTS parameter.

The values for LSB_MAX_JOB_DISPATCH_PER_SESSION and MAX_SBD_CONNS are not changed dynamically. If hosts are added dynamically, mbatchd does not increase their values. Once all the hosts are added, you must run the badmin mbdrestart command to set the correct values. If you know in advance that the number of hosts in your cluster will dynamically grow or shrink, then you should configure these parameters beforehand.