Platform LSF Command Reference - SAS

subIf the host group contains the keyword all, LSF dispatches the job to any available host,even if the host is not defined for the specified queue.To display configured host groups and compute units, use bmgroup.For the MultiCluster job forwarding model, you cannot specify a remote host by name.For parallel jobs, specify first execution host candidates when you want to ensure thata host has the required resources or runtime environment to handle processes that runon the first execution host.To specify one or more hosts or host groups as first execution host candidates, add the(!) symbol after the host name, as shown in the following example:bsub -n 2 -m "host1 host2! hostgroupA! host3 host4" my_parallel_jobLSF runs my_parallel_job according to the following steps:1. LSF selects either host2 or a host defined in hostgroupA as the first execution hostfor the parallel job.Note:First execution host candidates specified at the job-level(command line) override candidates defined at the queuelevel (in lsb.queues).2. If any of the first execution host candidates have enough processors to run the job,the entire job runs on the first execution host, and not on any other hosts.In the example, if host2 or a member of hostgroupA has two or more processors,the entire job runs on the first execution host.3. If 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 filelsb.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 executionhost.• Do not specify a preference (+) for a host identified by (!) as a first executionhost candidate.• For each parallel job, specify enough regular hosts to satisfy the processorrequirement for the job. Once LSF selects a first execution host for the currentjob, the other first execution host candidates become unavailable to the currentjob, but remain available to other jobs as either regular or first execution hosts.• You cannot specify first execution host candidates when you use the bruncommand.In a MultiCluster environment, insert the (!) symbol after the cluster name, as shownin the following example:bsub -n 2 -m "host2@cluster2! host3@cluster2" my_parallel_jobPlatform LSF Command Reference 223