Implementing a Virtual Server Environment: Getting Started

• Integrity VMs and vPars cannot be used within the same nPar.
• Each Integrity VM currently limited to 8 cores.
• Hardware resources are shared, so not a good choice if dedicated hardware is required.
• Not supported on PA-RISC systems.
• There is a slight decrease in performance for I/O, so not the best choice for I/O-intensive
applications. Note that newer releases of Integrity Virtual Machines deliver improved I/O
performance using Accelerated Virtual I/O drivers that streamline and re-architect the I/O
path for both networking and disk I/O.
Sweet Spots
• Good choice for applications that do not need dedicated hardware (or an entire CPU) but do
need OS isolation, different OS versions, different OS types, or a unique version of the
application stack.
• Good choice for non-cell-based systems that need a partitioning solution (if they are not I/O
intensive).
• Applications with spiky workloads can often get more than their entitlement of CPU cycles if
the other virtual machines are not demanding those cycles.
• Easy for deploying a new application or a new instance of an existing application by
creating a new virtual machine.
Why choose Resource Partitions or Secure Resource Partitions (SRPs)?
Key Benefits
• HP Process Resource Manager (PRM) product can be used to manage system resources (CPU,
memory, and disk I/O bandwidth) according to a user-defined priority by placing processes
in processor sets (PSETs) or Fair Share Scheduler (fss) groups.
• The granularity of resource allocation for PSETs is at the whole-CPU or core level.
• The granularity for resource allocation when using fss groups is sub-CPU (as little as 1%)
• Does not require a separate instance of the OS, as do vPars or Integrity VMs.
• Memory and I/O can be shared; memory entitlements can be reallocated on line.
• Supported on both HP 9000 and HP Integrity server systems; runs on both cell-based and
non-cell-based systems.
• Can save significant amount of money on software licenses when application stacking by
reducing the number of OS instances required.
• Workload Manager (WLM) can be used to add goal-based workload management and
automation of iCAP resource usage.
• By using the Security Containment feature of HP-UX, you can place one or more secure
compartments in PRM groups to create a Secure Resource Partition (SRP). Processes in each
SRP are isolated and cannot communicate with or access the resources of processes in other
SRPs.
Trade-offs
• No hardware isolation (same as vPars and Integrity VMs).
• No OS isolation or flexibility because Resource Partitions or SRPs are in the same OS.
• Supported only on HP-UX.
• Requires same patch levels and kernel tunables because all partitions in the same OS.
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