A rack mountable solid-state storage subsystem includes a plurality of interface units and a plurality of data storage modules to implement a mass storage device. Each of the interface units may be coupled to a plurality of communication ports for connection to a host server and to other interface units. Each data storage module may be detachably mated to a corresponding connector mounted to a motherboard. Each data storage module may also include a non-volatile flash memory storage and a volatile storage. The data storage modules may be partitioned into a plurality of portions, each coupled to a respective interface unit via the motherboard. Each portion of the data storage modules and the respective interface unit to which each portion is coupled may form a separate storage domain that is isolated from each other domain. The storage subsystem may also include redundant power supplies and backup power supplies.