<P> On IBM System p POWER hardware, LPARs are managed by PHYP (the POWER Hypervisor). PHYP acts as a virtual switch between the LPARs and also handles the virtual SCSI traffic between LPARs . Micro-Partitioning supports 10 times as many LPARs as processors with fractional allocations . It was introduced with the POWER5 processor . All IBM POWER5 and POWER6 systems may be partitioned . Note that a full system partition may be defined where all resources are consumed by a single partition . System P servers with PowerVM enabled allow LPARs with shared CPUs to delegate their unused cycles into the shared pool . Dedicated processors are not available for sharing . Unused cycles become available for other partitions and are governed by the parameters specified when the LPAR is defined . Changes to a running partition can be made dynamically up to the maximum value set, and down to the minimum value set in the active profile . The changing of resource allocations without restart of the logical partition is called dynamic logical partitioning . IBM PowerVM is the licensed / purchased feature that enables the virtualization features on p4, 5, 6, 7 series servers . </P> <P> Expoiting Intel vPro (i.e. Non-uniform memory access), there are also implementations of Logical Partitioning based on Intel Xeon e.g. by Hitachi Data Systems . </P> <P> LPARs safely allow combining multiple test, development, quality assurance, and production work on the same server, offering advantages such as lower costs, faster deployment, and more convenience . IBM mainframe LPARs are Common Criteria EAL5 certifiable, equivalent to physically unconnected servers, so they support the highest security requirements, including military use . Nearly all IBM mainframes run with multiple LPARs with the IBM System z9 and IBM System z10 supporting up to 60 LPARs . </P>

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