Administering Platform LSF - SAS

Chapter 16
Resource Allocation Limits
Resource allocation limits and resource usage limits
Resource allocation limits are not the same as resource usage limits, which
are enforced during job run time. For example, you set CPU limits, memory
limits, and other limits that take effect after a job starts running. See Chapter 26,
“Runtime Resource Usage Limits” for more information.
How LSF enforces limits
How LSF counts resources
Job slot limits
Resource
reservation and
backfill
MultiCluster
Resource allocation limits are enforced so that they apply to:
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Several kinds of resources:
❖ Job slots by host
❖ Job slots per processor
❖ Memory (MB or percentage)
❖ Swap space (MB or percentage)
❖ Tmp space (MB or percentage)
❖ Software licenses
❖ Other shared resources
Several kinds of resource consumers:
❖ Users and user groups (all users or per-user)
❖ Hosts and host groups (all hosts or per-host)
❖ Queues (all queues or per-queue)
❖ Projects (all projects or per-project)
All jobs in the cluster
Combinations of consumers:
❖ For jobs running on different hosts in the same queue
❖ For jobs running from different queues on the same host
Resources on a host are not available if they are taken by jobs that have been
started, but have not yet finished. This means running and suspended jobs
count against the limits for queues, users, hosts, projects, and processors that
they are associated with.
Job slot limits often correspond to the maximum number of jobs that can run
at any point in time. For example, a queue cannot start jobs if it has no job
slots available, and jobs cannot run on hosts that have no available job slots.
When processor or memory reservation occurs, the reserved resources count
against the limits for users, queues, hosts, projects, and processors. When
backfilling of parallel jobs occurs, the backfill jobs do not count against any
limits.
Limits apply only to the cluster where lsb.resources is configured. If the
cluster leases hosts from another cluster, limits are enforced on those hosts as
if they were local hosts.
Administering Platform LSF 259