HP-UX Workload Manager overview

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Introduction
Today, most servers are highly underutilized. While average utilization varies by customer and
operating system, in the HP-UX environment it is often around 30%. There are myriad reasons for this
utilization, but one of the primary reasons is that customers often have one application per server,
and they size that server for a peak load of typically three to five times the average utilization. This
means that millions of dollars in server resources—CPU resources and memory—can lie idle for most
of the time.
Resource optimization, which is one of the goals of the HP Adaptive Enterprise strategy, enables you
to combine applications while maintaining performance. The Adaptive Enterprise strategy helps
customers synchronize business and IT resources to adapt to and capitalize on change. To help you
realize the promise of becoming an Adaptive Enterprise, HP provides virtualization technologies that
pool and share resources to optimize utilization and meet demands automatically.
HP-UX Workload Manager (WLM) is a virtualization solution that helps you achieve a true Adaptive
Enterprise. As a goal-based policy engine in the HP Virtual Server Environment (VSE), WLM integrates
virtualization techniques—including partitioning, resource management, utility pricing resources, and
clustering—and links them to your service level objectives (SLOs) and business priorities. WLM
enables a virtual HP-UX server to grow and shrink automatically based on the demands and SLOs for
each application it hosts. WLM helps you receive greater return on your IT investment while ensuring
that end-users receive the service and performance they expect.
The HP Virtual Server Environment offers several forms of partitioning that WLM can manage:
• Hard partitions—Hard partitions are implemented and isolated through hardware. The first form of
hard partitions is a complete server, which can be clustered in an HP Serviceguard high-availability
cluster configuration. nPartitions, which are portions of a single server, are other forms of hard
partitions. Each hard partition runs its own instance of HP-UX. Isolation provided by nPartitions
guarantees that an application running in one partition is not affected by an application or
hardware failure in another.
• Virtual partitions—Virtual partitions are implemented and isolated through software, with each
virtual partition running its own instance of the HP-UX operating system. HP virtual partitions offer
unique granularity for partitioning servers. You can create a virtual partition consisting of one or
more cores, and you can use virtual partitions within hard partitions. (A core is the actual data
processing engine within a processor, where a single processor can have multiple cores.) Virtual
partitions provide complete software isolation between partitions.
• Virtual machines—Virtual machines, much like virtual partitions, are created with software.
However, they emulate generic servers and, therefore, can offer subcore and shared I/O
capabilities. Each virtual machine runs its own operating system. HP Integrity Virtual Machines can
be used within hard partitions.
• Resource partitions—Resource partitions are provided by HP Process Resource Manager (PRM) to
manage processor sets and Fair Share Scheduler (FSS) groups. These partitions enable you to
partition system resources (including memory and disk bandwidth) within a single instance of HP-UX
and consolidate multiple workloads within that instance. You can use these partitions within (but not
across) hard partitions and virtual partitions.
You can use WLM to manage system resources within resource partitions, in which case WLM creates
and manages its own PRM configuration (PRM must be installed on the same system). You can use
WLM to manage CPU resources across hard partitions and virtual partitions. WLM automatically
moves cores between partitions based on the SLOs in the partitions. (Given the physical nature of
hard partitions, the “movement” of cores among partitions is achieved by deactivating a core on one
nPartition and then activating a core on another.) You can use WLM to manage resources within a
virtual machine. On an Integrity Virtual Machines (Integrity VM) host, you can use WLM to manage