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Chapter 1. Introduction=======================

PowerVM Editions****************1. The PowerVM Express Edition

* available on the POWER6 technology-based System p550 and System p520 Expres

s servers* Up to three partitions per server* Shared dedicated capacity

2. PowerVM Standard Edition* supports POWER5 and POWER6* Multiple Shared Processor pools for POWER6-based systems

3. PowerVM Enterprise Edition* only available on the new POWER6-based systems* PowerVM Live Partition Mobility to the suite of functions.

POWER Hypervisor****************The POWER Hypervisor is always active on POWER5- and POWER6-based servers, the POWERHypervisor is responsible for dispatching the logical partition workload acrosstheshared physical processors. The POWER Hypervisor also enforces partitionsecurity, and can provide inter-partition communication that enables the VirtualI/O Servers virtual SCSI and virtual Ethernet function.

Simultaneous multithreading***************************Simultaneous multithreading (SMT) is an IBM microprocessor technology that

allows two separate hardware instruction streams (threads) to run concurrentlyon the same physical processor.Supports on POWER5 and POWER6.

Logical partitions******************A set of system resources: whole POWER microprocessors, memory, and I/O resourcesare logically grouped into a partitionan LPAR. Because resource allocation is alogical function, the amount of resources can vary according to need andavailability within the physical server.

Available in IBM POWER-based systems since 2001 with the introduction of the IBMpSeries 690, a POWER4-based server.

Micro-partitions****************These shared-processor partitions, known as micro-partitions, are allocatedprocessor resources from a single pool of physical processors.

Entitled capacity*****************The amount of processor capacity that is allocated to a micro-partitionitsentitled capacitymay range from ten percent (10%) of a physical processor upto the entire capacity of the physical shared processor pool. The physical share

dprocessor pool can have from one physical processor up to the total installedprocessor capacity of the system.

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Changes to the entitled capacity of a micro-partition can be as granular as onepercent (1%) of a physical processor.

Micro-partitions can be designated as either capped or uncapped.

Capped

******A capped micro-partition has a defined processor entitled capacity which it isguaranteed to receive. There are no circumstances under which a cappedmicro-partition will receive any more processor resource than its entitledcapacity.

Uncapped********An uncapped micro-partition has a defined processor entitled capacity whichit is guaranteed to receive. However, under some circumstances it canreceive additional processor resources. Typically, if the uncappedmicro-partition is runnable (has real work to execute) and there are unused

processor cycles within the physical shared processor pool, then additionalcycles can be allocated to the micro-partition on a weighted basis.

Capped and uncapped micro-partitions can coexist and both receive theprocessor resources from the physical shared-processor pool.

Multiple Shared-Processor Pools (MSPP)**************************************On POWER6-based systems there is support for Multiple Shared-ProcessorPools. This new capability allows a systems administrator to create a set ofmicro-partitions with the purpose of controlling the processor capacity that theycan consume from the physical shared-processor pool.

Multiple Shared-Processor Pools use processor capacity from the physicalshared processor poolthere can only be one physical shared processor pool inthe system. Each Shared-Processor Pool has an associated Entitled PoolCapacity which is consumed by the set of micro-partitions in thatShared-Processor Pool.

The micro-partitions within a Shared-Processor Pool are guaranteed to receivetheir entitled capacity. In addition, unused processor cycles within theirShared-Processor Pool are harvested and are redistributed to eligiblemicro-partitions within the same Shared-Processor Pool.

There can be up to 64 MSPPs in total. With the default MSPP, there can be anadditional 63 MSPPs that are user-defined.

Reserved Pool Capacity**********************The source of additional processor cycles can be the Reserved Pool Capacity,which is processor capacity specifically reserved for a Shared-Processor Poolbut not assigned to any of the micro-partitions in the Shared-Processor Pool.

Processor capacity from other Shared-Processor Pool***************************************************When the set of micro-partitions in a Shared-Processor Pool are heavily loaded,they can consume additional processor capacity (assuming they are uncapped)

from outside their Shared-Processor Pool up to a defined maximum, MaximumPool Capacity. Processor capacity distributed in this way has been ceded byunderutilized sets of micro-partitions in their Shared-Processor Pools.

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Default Shared-Processor Pool*****************************There is a default Shared-Processor Pool (Shared-Processor Pool0) that is usedfor all micro-partitions if the system administrator has not created otherShared-Processor Pools.

Shared dedicated capacity*************************POWER6-based servers offer the capability of harvesting unused processorcycles from dedicated-processor partitions. These unused cycles are thendonated to the physical shared-processor pool associated withmicro-partitioning. This ensures the opportunity for maximum processorutilization throughout the system.

Dynamic LPAR (DLPAR)********************It is possible to dynamically move system resources between partitions withoutrebooting. These resources can be:

* Physical processors (for dedicated processor LPARs)* Virtual processors or entitled capacity (for micro-partitions)* Memory* Physical I/O adapters* Virtual I/O adapters

Virtual Ethernet****************The virtual Ethernet function is provided by the POWER Hypervisor. ThePOWER Hypervisor implements the Ethernet transport mechanism as well as anEthernet switch that supports VLAN capability. Virtual LAN allows securecommunication between logical partitions without the need for a physical I/Oadapter or cabling. The ability to securely share Ethernet bandwidth across

multiple partitions increases hardware utilization.

Virtual I/O Server******************As part of PowerVM there is an appliance server with which you can associatephysical resources and that allows you to share these resources amongst agroup of logical partitions. The Virtual I/O Server can use both virtualized storageand network adapters, making use of the virtual SCSI and virtual Ethernetfacilities.

The Virtual I/O Server technology facilitates the consolidation of LAN and diskI/O resources and minimizes the number of physical adapters that are required,while meeting the non-functional requirements of the server.

The Virtual I/O Server can run in either a dedicated processor partitionor amicro-partition.

Shared Ethernet Adapters (SEA)******************************Shared Ethernet Adapters bridging network traffic from the virtual Ethernet networks out to physicalEthernet networks.

Live Partition Mobility

***********************Live Partition Mobility, licensed through PowerVM Enterprise Edition, is a feature

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that relies on a number of different components, including:* POWER Hypervisor* Virtual I/O Server (or IVM)* Hardware Management Console (or IVM)Live Partition Mobility allows you to move running AIX or Linux partitions fromone physical POWER6 server to another without disruption.

Capacity Upgrade on Demand (CUoD)*********************************With Capacity Upgrade on Demand (CUoD), you can activate additional processors and memory units on selected servers by purchasing a permanent processor or memory unit activation feature. CUoD adds capacity for new workloads, which enables your server to adapt to unexpected performance demands.

Redundant Virtual I/O Servers*****************************Since an AIX or Linux partition can be a client of one or more Virtual I/O Serversat the same time, a good strategy to improve availability for sets of AIX or Lin

uxclient partitions is to connect them to two Virtual I/O Servers. One key reasonforredundancy is the ability to upgrade to the latest Virtual I/O Server technologieswithout affecting production workloads.

Security in a virtualized environment*************************************In POWER5 and POWER6 machines all resources are controlled by the POWERHypervisor. The POWER Hypervisor ensures that any partition attempting toaccess resources within the system has permission to do so.