In the example, if host2 or a member of hostgroupA has two or more processors, the entire job runs on the first execution host.

3If the first execution host does not have enough processors to run the entire job, LSF selects additional hosts that are not defined as first execution host candidates.

Follow these guidelines when you specify first execution host candidates:

❖If you specify a host group, you must first define the host group in the file

lsb.hosts.

❖Do not specify a dynamic host group as a first execution host.

❖Do not specify all, allremote, or others, or a host partition as a first execution host.

❖Do not specify a preference (+) for a host identified by (!) as a first execution host candidate.

❖For each parallel job, specify enough regular hosts to satisfy the processor requirement for the job. Once LSF selects a first execution host for the current job, the other first execution host candidates become unavailable to the current job, but remain available to other jobs as either regular or first execution hosts.

❖You cannot specify first execution host candidates when you use the brun command.

In a MultiCluster environment, insert the (!) symbol after the cluster name, as shown in the following example:

bsub -n 2 -m "host2@cluster2! host3@cluster2" my_parallel_job

-migmigration_threshold

Specifies the migration threshold for checkpointable or rerunnable jobs in minutes. Enables automatic job migration and specifies the migration threshold, in minutes. A value of 0 (zero) specifies that a suspended job should be migrated immediately.

Command-level job migration threshold overrides application profile and queue-level settings.

Where a host migration threshold is also specified, and is lower than the job value, the host value is used.

-nmin_proc[,max_proc]

Submits a parallel job and specifies the number of processors required to run the job (some of the processors may be on the same multiprocessor host).

You can specify a minimum and maximum number of processors to use. The job can start if at least the minimum number of processors is available. If you do not specify a maximum, the number you specify represents the exact number of processors to use.

If PARALLEL_SCHED_BY_SLOT=Y in lsb.params, this option specifies the number of slots required to run the job, not the number of processors.

Jobs that request fewer slots than the minimum PROCLIMIT defined for the queue or application profile to which the job is submitted, or more slots than the maximum PROCLIMIT are rejected. If the job requests minimum and maximum

Platform LSF Command Reference 193