114 IBM BladeCenter PS703 and PS704 Technical Overview and IntroductionThe SDMC or IVM is used to configure, validate, and orchestrate Live Partition Mobility onPOWER-based blades. Use the SDMC to enable mover service function for Virtual I/OServer; an SDMC or IVM wizard validates your configuration and identifies issues that willcause the migration to fail. During the migration, the SDMC or IVM controls all phases of theprocess.3.4.7 Active Memory SharingActive Memory Sharing is an IBM PowerVM advanced memory virtualization technology thatprovides system memory virtualization capabilities to IBM Power Systems, allowing multiplepartitions to share a common pool of physical memory. Active Memory Sharing is onlyavailable with PowerVM Enterprise edition.The physical memory of an IBM POWER6 or POWER7 system can be assigned to multiplepartitions in either a dedicated or a shared mode. The system administrator has the capabilityto assign physical memory to a partition and physical memory to a pool that is shared byother partitions. A single partition can have either dedicated or shared memory.In a dedicated memory model, the system administrator’s task is to optimize availablememory distribution among partitions. When a partition has performance degradation due tomemory constraints and other partitions have unused memory, the administrator can allocatememory by doing a DLPAR operation.With a shared memory model, it is the system (PowerVM Hypervisor) that automaticallydecides the optimal distribution of the physical memory to partitions and adjusts the memoryassignment based on partition load.Active Memory Sharing can be exploited to increase memory use on the system either bydecreasing the system memory requirement or by allowing the creation of additionalpartitions on an existing system. Active Memory Sharing can be used in parallel with ActiveMemory Expansion on a system running a mixed workload of several operating systems. Forexample, AIX partitions can take advantage of Active Memory Expansion while otheroperating systems take advantage of Active Memory Sharing.For additional information regarding Active Memory Sharing see PowerVM VirtualizationActive Memory Sharing, REDP-4470, available from:http://www.redbooks.ibm.com/abstracts/redp4470.htmlFigure 3-13 on page 115 shows each logical partition can be configured to have sharedmemory using Active Memory Sharing or dedicated memory.
