Dynamic Logical Partitioning
Dynamic Logical Partitioning (DLPAR), is a capability of a logical partition (LPAR) to be reconfigured dynamically, without shutting it down. It enables memory, CPU capacity, and I/O interfaces to be moved between LPARs.
IBM introduced DLPAR on POWER4-based servers in 2001 as a mainframe-inspired technology. It is supported on AIX and i5/OS. The Linux kernel for POWER supports DLPAR, although changes are limited to CPU capacity and PCI devices (not memory).
Later, the POWER5 processor added more capabilities, including micro-partitioning: up to ten LPARs could be configured per processor, with a single multiprocessor server supporting a maximum of 254 LPARs (and thus up to 254 independent operating systems).
The System z9 and zSeries mainframes and their operating systems, including Linux on zSeries, support even more sophisticated forms of dynamic LPARs. Relevant LPAR-related features on those mainframe platforms include Intelligent Resource Director, Sysplex, Parallel Sysplex, Geographically Dispersed Parallel Sysplex, and Hipersockets. The System z9 supports up to 60 LPARs on a single server, but mainframes also support an additional level of virtualization using z/VM with the ability to support thousands of operating system instances on a single server.