If you specify a host group or compute unit, you must first define the host group or compute unit 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.
You cannot specify first execution host candidates when you use the brun command.
If the first execution host is incorrect at job submission, the job is rejected. If incorrect configurations exist on the queue level, warning messages are logged and displayed when LSF starts, restarts or is reconfigured.
bsub -n 2 -m "hostA! hostB hostC" myjobbsub -n 2 -m "hostA hostB hostC" myjobbsub -n 2 -m "hostA hostB! hostC" myjob
For job chunking, all jobs must request the same hosts and the same first execution hosts (if specified). Jobs that specify a host preference must all specify the same preference.
If you specify first execution host candidates at the job or queue level, LSF tries to reserve a job slot on the first execution host. If LSF cannot reserve a first execution host job slot, it does not reserve slots on any other hosts.
If compute units resource requirements are used, the compute unit containing the first execution host is given priority:
bsub -n 64 -m "hg! cu1 cu2 cu3 cu4" -R "cu[pref=config]" myjob
In this example the first execution host is selected from the host group hg. Next in the job’s allocation list are any appropriate hosts from the same compute unit as the first execution host. Finally remaining hosts are grouped by compute unit, with compute unit groups appearing in the same order as in the ComputeUnit section of lsb.hosts.