Use exclusive scheduling
Exclusive scheduling gives a job exclusive use of the host that it runs on. LSF dispatches the job to a host that has no other jobs running, and does not place any more jobs on the host until the exclusive job is finished.
Compute unit exclusive scheduling gives a job exclusive use of the compute unit that it runs on.
How exclusive scheduling works
When you submit an exclusive job (bsub -x) to an exclusive queue (the queue defines the EXCLUSIVE = Y or EXCLUSIVE = CU parameter in the lsb.queues file) and dispatched to a host, LSF locks the host (lockU status) until the job finishes.
LSF cannot place an exclusive job unless there is a host that has no jobs running on it.
To make sure exclusive jobs can be placed promptly, configure some hosts to run one job at a time. Otherwise, a job could wait indefinitely for a host in a busy cluster to become completely idle.
Resizable jobs
For pending allocation requests with resizable exclusive jobs, LSF does not allocate slots on a host that is occupied by the original job. For newly allocated hosts, LSF locks the LIM if the LSB_DISABLE_LIMLOCK_EXCL=Y parameter is not defined in the lsf.conf file.
If an entire host is released by a job resize release request with exclusive jobs, LSF unlocks the LIM if LSB_DISABLE_LIMLOCK_EXCL=Y is not defined in lsf.conf.