1. A system, comprising: a controller operable to accept commands for reading or writing data; and a plurality of memory modules each memory module having a physical address range, including a spare memory module, in communication with the controller over a bus; wherein the controller is configured to: store data in a group of memory modules of the plurality of memory modules configured as a RAID group with erase hiding; migrate data from a first memory module of the plurality of memory modules to the spare memory module while maintaining erase hiding; determine when the first memory module is replaced with a memory module having a larger physical address range; manage an association of a global logical address space having a range at least equal to a maximum system physical address space: wherein each memory module has a physical address range and addresses of the global logical address space are mapped to the physical address range; a mapped range of the global logical address space being a sum of the physical address ranges of the memory modules; and the larger physical address range of the memory module is mapped to a previously unmapped range of addresses of the global logical address-space.