Backfill scheduling requires all jobs to specify a duration. If you specify a run time limit using the command line bsub -W option or by defining the RUNLIMIT parameter in lsb.queues or lsb.applications, LSF uses that value as a hard limit and terminates jobs that exceed the specified duration. Alternatively, you can specify an estimated duration by defining the RUNTIME parameter in lsb.applications. LSF uses the RUNTIME estimate for scheduling purposes only, and does not terminate jobs that exceed the RUNTIME duration.