A method and apparatus implement redundant memory access using multiple controllers for a memory system, and a design structure on which the subject circuit resides are provided. A first memory controller uses a first memory and a second memory controller uses the second memory as its respective primary address space, for storage and fetches. The second memory controller is also connected to the first memory. The first memory controller is also connected to the second memory. The first memory controller and the second memory controller, for example, are connected together by a processor communications bus. When one of the first memory controller or the second memory controller fails, then the other memory controller is notified. The other memory controller takes control of the memory for the failed controller, using the direct connection to that memory, and maintains coherence of both the first memory and second memory.