A memory system including a first central processing unit, a first memory module connected to the first central processing unit by a first channel, a second memory module connected to the first central processing unit by a second channel, and a third memory module connected to the first central processing unit by a third channel may be provided. Each of the first memory module, the second memory module, and the third memory module may be configured to write the same data in a data area thereof and a mirroring data area thereof in response to an address in a mirroring mode.