Platform LSF Administration Guide Version 6.2

Chapter 2
How the System Works
Administering Platform LSF
69
Automatic queue selection
Typically, a cluster has multiple queues. When you submit a job to LSF you might define
which queue the job will enter. If you submit a job without specifying a queue name, LSF
considers the requirements of the job and automatically chooses a suitable queue from
a list of candidate default queues. If you did not define any candidate default queues, LSF
will create a new queue using all the default settings, and submit the job to that queue.
Viewing default
queues
Use bparams to display default queues:
% bparams
Default Queues: normal
...
The user can override this list by defining the environment variable
LSB_DEFAULTQUEUE.
How automatic
queue selection
works
LSF selects a suitable queue according to:
◆ User access restriction—Queues that do not allow this user to submit jobs are not
considered.
◆ Host restriction—If the job explicitly specifies a list of hosts on which the job can
be run, then the selected queue must be configured to send jobs to all hosts in the
list.
◆ Queue status—Closed queues are not considered.
◆ Exclusive execution restriction—If the job requires exclusive execution, then
queues that are not configured to accept exclusive jobs are not considered.
◆ Job’s requested resources—These must be within the resource allocation limits of
the selected queue.
If multiple queues satisfy the above requirements, then the first queue listed in the
candidate queues (as defined by the DEFAULT_QUEUE parameter or the
LSB_DEFAULTQUEUE environment variable) that satisfies the requirements is
selected.
Job files
When a batch job is submitted to a queue, LSF Batch holds it in a job file until conditions
are right for it to be executed. Then the job file is used to execute the job.
UNIX
The job file is a Bourne shell script run at execution time.
Windows
The job file is a batch file processed at execution time.