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In a sense, memory mirroring is the opposite of transparent page sharing, in that instead of combining duplicate memory pages into one page to free up memory for other VMs, a the hypervisor creates a redundant copy of memory. Although memory consumption essentially doubles, with memory mirroring, you have a reliable backup, which improves VM reliability. If something happens to the first channel, the memory controller can shift to the second channel without disrupting operations. When the issue is resolved, the channels are synchronized again. This technique can also be used with other memory management techniques, like memory sparing, where hot spare memory modules are integrated when there is a problem with active memory modules. In general, memory mirroring allows for higher memory consolidation.