A memory system and methods for memory manage are presented. The memory system includes a volatile memory electrically connected to a high-density memory; a memory controller that expects data to be written or read to or from the memory system at a bandwidth and a latency associated with the volatile memory; a directory within the volatile memory that associates a volatile memory address with data stored in the high-density memory; and redundant storage in the high-density memory that stores a copy of the association between the volatile memory address and the data stored in the high-density memory. The methods for memory management allow writing to and reading from the memory system using a first memory read/write interface (e.g. DRAM interface, etc.), though data is stored in a device of a different memory type (e.g. FLASH, etc.).