LSF Version 7.3 - Administering Platform LSF

Configuring Resource Allocation Limits
398 Administering Platform LSF
Reservation and
backfill
Reservation and backfill are still made at the job slot level, but despite a slot
reservation being satisfied, the job may ultimately not run because the JOBS limit
has been reached. This similar to a job not running because a license is not
available.
Other jobs ◆ brun forces a pending job to run immediately on specified hosts. A job forced
to run with
brun is counted as a running job, which may violate JOBS limits.
After the forced job starts, the JOBS limits may be exceeded.
◆ Requeued jobs (brequeue) are assigned PEND status or PSUSP. Usage of JOBS
limit is decreased by the number of requeued jobs.
◆ Checkpointed jobs restarted with brestart start a new job based on the
checkpoint of an existing job. Whether the new job can run depends on the
limit policy (including the JOBS limit) that applies to the job. For example, if
you checkpoint a job running on a host that has reached its JOBS limit, then
restart it, the restarted job cannot run because the JOBS limit has been reached.
◆ For job arrays, you can define a maximum number of jobs that can run in the
array at any given time. The JOBS limit, like other resource allocation limits,
works in combination with the array limits. For example, if JOBS=3 and the
array limit is 4, at most 3 job elements can run in the array.
◆ For chunk jobs, only the running job among the jobs that are dispatched
together in a chunk is counted against the JOBS limit. Jobs in WAIT state do not
affect the JOBS limit usage.
Example limit configurations
Each set of limits is defined in a Limit section enclosed by Begin Limit and End
Limit.
Example 1 user1 is limited to 2 job slots on hostA, and user2’s jobs on queue normal are
limited to 20 MB of memory:
Begin Limit
NAME HOSTS SLOTS MEM SWP TMP USERS QUEUES
Limit1 hostA 2 - - - user1 -
- - - 20 - - user2 normal
End Limit
Example 2 Set a job slot limit of 2 for user user1 submitting jobs to queue normal on host
hosta for all projects, but only one job slot for all queues and hosts for project test:
Begin Limit
HOSTS SLOTS PROJECTS USERS QUEUES
hosta 2 - user1 normal
- 1 test user1 -
End Limit
Example 3 Limit usage of hosts in license1 group:
◆ 10 jobs can run from normal queue
◆ Any number can run from short queue, but only can use 200 MB of memory
in total