Memory Mirroring

What Does Memory Mirroring Mean?

Memory mirroring is a technique used to separate memory into two separate channels, usually on a memory device, like a server. In memory mirroring, one channel is copied to another to create redundancy. This method makes input/output (I/O) registers and memory appear with more than one address range because the same physical byte is accessible at more than one address. Using memory mirroring, higher memory reliability and a higher level of memory consolidation are possible.


Techopedia Explains Memory Mirroring

The advantages of memory mirroring include the following:

  • In the event of failures, like Dual In-line Memory Module (DIMM) failure, the overall system remains unaffected and operational, allowing processes to continue without unscheduled downtime. This is because the memory controller shifts to the other channel without any disruption, and synchronization between channels is established after the issues are resolved.
  • With regard to memory processors, memory mirroring facilitates the attainment of the highest possible consistency between memories.
  • It is independent of the operating system (OS) used, as it is built into the memory controller. It runs just as easily in Linux and Windows.
  • It may be coupled with memory sparing for integrating and installing other hot spare memory modules, as needed.
  • It provides full protection for single bit and multiple bit errors.

Memory mirroring’s key disadvantage is the higher memory cost required to create this redundancy.


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Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.