What is HP-UX Workload Manager?

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 business priorities and service level objectives (SLOs). WLM enables a virtual HP-UX server to grow and shrink automatically, based on the demands and SLOs for each application it hosts. You can consolidate multiple applications onto a single server to receive greater return on your IT investment while ensuring that end-users receive the service and performance they expect.

WLM manages CPU resources (cores) within and across hard partitions and virtual partitions. (A core is the actual data-processing engine within a processor, where a processor might have multiple cores.) It automatically adapts partitions’ CPU resources to the demands, SLOs, and priorities of the applications running in those partitions. On systems with HP Instant Capacity (iCAP), WLM automatically moves cores among 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.

A workload is a group of processes that are treated as a single unit for the purposes of resource management. For example, a database application that consists of multiple cooperating processes is considered a workload. WLM is most effective managing applications that are CPU-bound. It adjusts the CPU allocation of a workload based on current needs and performance of that workload’s applications.

HP-UX WLM manages workloads based on parameters defined within a configuration file. You define one or more SLOs for each workload, and you can prioritize the SLOs so that an SLO assigned a higher priority is given precedence over lower-priority SLOs. HP-UX WLM then manages each workload’s resources, automatically allocating resources to achieve the desired service level objectives.

HP-UX WLM automates many of the features of PRM (Process Resource Manager) and HP-UX Virtual Partitions (vPars), including automatic re-allocation of resources in response to SLO performance.

WLM is optimized for moving and balancing CPU resources across partitions. Using hosts as workloads, WLM manages workload allocations while maintaining the isolation of their HP-UX instances.

You can also use WLM to manage workloads so that resources are divided and shared within a single HP-UX instance. These workloads are based on PRM groups: Fair Share Scheduler (FSS) groups or groups based on processor sets (PSETs). Within a single HP-UX instance, WLM can manage a group’s CPU resources as well as real memory and disk bandwidth. (Real memory and disk bandwidth allocations are statically assigned in the configuration file.) When you configure WLM, you define workload groups and assign processes to them based on specific applications, users, or Unix groups. You can also create your own criteria for placing application processes in specific workload groups by defining process maps. In a process map, you map a group to a script or command and its arguments that gathers process IDs and causes the identified processes to be assigned to the group. (The WLM SAP Toolkit, in conjunction with HP Serviceguard Extension for SAP [SGeSAP], takes advantage of process maps, providing a script that enables you to place specified SAP processes in specific workload groups managed by WLM. For more information, see Chapter 5 “HP-UX WLM SAP Toolkit”.) Another way to assign processes to workload groups is by assigning secure compartments to the workload groups. You create the secure compartment with the HP-UX feature Security Containment. Secure compartments isolate files and processes. WLM can then automatically allocate resources for these secure compartments.

Using WLM in combination with HP-UX Workload Manager Toolkits (WLMTK), you can quickly and effectively deploy WLM for use with your key applications.