Administering Platform LSF - SAS

Chapter 14
Fairshare Scheduling
Cross-queue Fairshare
Applying the same fairshare policy to several queues
User and queue priority
Fairshare policy configured at the queue level handles resource contention
across multiple queues.
You can define a fairshare policy that applies to several queues at the same
time. You define the fairshare policy in a master queue and list slave queues
to which the same fairshare policy applies; slave queues inherit the same
fairshare policy as your master queue. For job scheduling purposes, this is
equivalent to having one queue with one fairshare tree.
In this way, if a user submits jobs to different queues, user priority is calculated
by taking into account all the jobs the user has submitted across the defined
queues.
To submit jobs to a fairshare queue, users must be allowed to use the queue
(USERS in lsb.queues) and must have a share assignment (FAIRSHARE in
lsb.queues). Even cluster and queue administrators cannot submit jobs to a
fairshare queue if they do not have a share assignment.
By default, a user has the same priority across the master and slave queues. If
the same user submits several jobs to these queues, user priority is calculated
by taking into account all the jobs the user has submitted across the masterslave
set.
If DISPATCH_ORDER=QUEUE is set in the master queue, jobs are dispatched
according to queue priorities first, then user priority. This avoids having users
with higher fairshare priority getting jobs dispatched from low-priority queues.
Jobs from users with lower fairshare priorities who have pending jobs in higher
priority queues are dispatched before jobs in lower priority queues. Jobs in
queues having the same priority are dispatched according to user priority.
Queues that are not part of the ordered cross-queue fairshare can have any
priority. Their priority can fall within the priority range of cross-queue fairshare
queues and they can be inserted between two queues using the same fairshare
tree.
Viewing cross-queue fairshare information
Run bqueues -l to know if a queue is part of cross-queue fairshare. The
parameter FAIRSHARE_QUEUES indicates cross-queue fairshare. The first
queue listed in the FAIRSHARE_QUEUES parameter is the master queue—the
queue in which fairshare is configured; all other queues listed inherit the
fairshare policy from the master queue.
All queues that participate in the same cross-queue fairshare will display the
same fairshare information (SCHEDULING POLICIES, FAIRSHARE_QUEUES,
USER_SHARES, SHARE_INFO_FOR) when bqueues -l is used. Fairshare
information applies to all the jobs running in all the queues in the master-slave
set.
Administering Platform LSF 211