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Chapter 5. Policies
5.1. Policies Overview
Moab Workload Manager has many powerful policies that can be managed to effectively get as much
workload out as possible while satisfying other desires. The policies section is intended to give control
over Workload Manager’s various policies.
5.2. Fairshare
Summary
Fairshare allows the cluster to be shared between different individuals and/or organizations without
allowing any individual or organization the ability to monopolize the cluster. This is achieved by tracking
how the cluster is used over time by each credential or user, group, class, account, and quality of service
(QoS) and raising or lowering the start priorities of jobs waiting to execute. It should be noted that the
start priority is used by Workload Manager to decide which jobs get executed first. The higher the start
priority, the sooner a job will execute. The information collected about each credential is inserted into
what is called a usage window. The length or amount of time tracked in a window is defined by the
system administrator.
Often times, system administrators can not achieve the cluster sharing they desire without using multiple
usage windows. Multiple usage windows allow Workload Manager to balance cluster usage differently
by making the most recent window more important than more outdated windows. This is achieved by
using the Usage Window Decay Factor. Essentially, the lower the decay factor, the less important
outdated usage windows are.
5.2.1. Fairshare Options
•
Interval Length - This field allows an administrator to define how long each window lasts.
•
Depth - This field allows an administrator to define how many windows should exist.
•
Usage Metric - This field allows an administrator to define how credential usage is tracked.
1. Dedicated PS - This field tracks credential usage according to the number of processor seconds
reserved for a job.
2. Dedicated PES - This field tracks credential usage according to the number of processor
equivalent seconds reserved for a job.
3. Utilized PS - This field tracks credential usage according to the number of processor seconds used
by a job.
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