This section discusses HP’s Virtual Server Environment (VSE) as well as vPars, nPartitions, and IVMs.
HP’s VSE is the front-end for HP’s overall virtualization strategies. VSE itself contains several elements, including a workload management tool and advanced manageability software. The workload management feature lets you draw from spare capacity, which is available on a pay-per-use basis. This is similar in many respects to IBM’s Capacity on Demand. Further, HP Global Workload Manager (gWLM) provides intelligent policy engines that allow for automatically adjusting the workloads to increase server utilization. It also comes with a product called HP Capacity Advisor, which helps you simulate various workload scenarios and is similar in many ways to IBM’s System workload Estimator (WLE), which ships with their System Planning Tool. The VSE also lets you partition in several ways, with hard and soft partitions, as well as HP Virtual machines, partitions, and secure resource partitions. HP describes their virtualization/partitioning solutions as their partitioning continuum. Available partitioning includes:
- nPartitions offers true electrical isolation as well as cell granularity. nPartitions are based on hard partitions, which were first introduced by HP in 2000 and offer greater fault isolation than soft partitions. nPartitions let you service one partition while others are online, which is similar to IBM’s logical partitioning, though systems require a reboot when moving cells from one partition to another. It’s important to note that while nPartitions support HP-UX, Windows®, VMS, and Linux, they only do so on their Itanium processor, not on their HP9000 PA Risc architecture. Partition scalability also depends on the operating system running in the nPartition. Another downside is that entry-level servers do not support this technology — only HP9000 and Integrity High End and Midrange servers. They also do not support moving resources to and from other partitions without a reboot.
- vPars are separate operating system instances on the same nPartition or server. This offering lets you dynamically move either CPU or memory resources between partitions as the workload requirements change. They also give you the ability to run multiple copies of HP-UX on the same hardware. Using vPars, you can move CPUs to other running partitions, similar to PowerVM and the System p. What you can’t do with vPars is share resources, because there is no virtualized layer in which to manage the interface between the hardware and the operating systems. This is one reason why performance overhead is limited, a feature that HP will market without discussing its clear limitations. The scalability is also restricted as to the nPartition that the vPar is created on, the max being an 8 cell limitation. There is also limited workload support; resources cannot be added or removed. Finally, vPars also don’t let you share resources between partitions, nor can you dynamically allocate processing resources between partitions.
- Integrity Virtual Machines (IVMs) are separate guest instances on the same nPartition with different operating system versions and users in a fully isolated environment. First introduced in 2005, they allow for a partition to have its own full copy of the operating system. Within this copy, the virtual machines share the resources. This is similar in many ways to IBM’s PowerVM, as there is granularity for CPUs and I/O device sharing. The granularity actually beats PowerVM because you can have up to 1/20 of a micropartition; the System p allows for only 1/10 of a CPU. The downside here is scalability. With HP’s virtual machines there is a 4 CPU limitation and RAM limitation of 64 GB. Reboots are also required to add processors or memory. There is no support for features such as uncapped partitions or shared processor pools. Finally, it’s important to note that HP PA RISC servers are not supported; only Integrity servers are supported. Virtual storage adapters also cannot be moved, unless the virtual machines are shut down. You also cannot dedicate processing resources to a single partition.
- Resource Partitions are created from the HP Process resource manager and allow resources for specific applications within a single operating system. This is also a resource management tool, which lets you manage CPU, memory, and disk bandwidth. It allows minimum allocations of CPUs, and even lets you cap a CPU by group. In many ways, this is similar to a Solaris container or AIX WPAR in that it lets you have several applications residing in one copy of HP-UX. This feature has been available since HP-UX 9.0.
With release 4.1, HP-UX now lets you have online workload migration, available on Integrity Virtual machines only. This is similar to AIX’s Live Application mobility. The March 2009 release, Version HP-UX 11iv3, also provides several enhancements, including the new
parconfig command, which provides help for the recommended configuration of nPartitions. It also provides support for accelerated virtual I/O (AVIO) for networking on Windows and Linux guests, which gives clients up to a two-fold improvement in throughput over older virtualized storage3 and integrity solutions, as well as a 60% reduction in service demand. It consists of two components: an Integrity VM host and a VM Guest component.
For more info, just go to HP website (http://www.hp.com).