Platform LSF Administration Guide Version 6.2

Cross-queue User-based Fairshare
Administering Platform LSF
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Cross-queue User-based Fairshare
User-based fairshare policies configured at the queue level handle resource contention
across multiple queues.
Applying the same fairshare policy to several queues
With cross-queue fairshare, the same user-based fairshare policy can apply to several
queues can 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.
User and queue priority
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 master-slave 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.
bqueues -l also displays DISPATCH_ORDER in the master queue if it is defined.