Redundant capacity in a memory system is utilized to facilitate active monitoring of solid state memory devices in the memory system. All or part of the data stored in an active solid state memory device, and used in an active data processing system, may be copied to at least one redundant memory device, e.g., by transitioning a memory address range that was allocated to the active memory device to the redundant memory device. By doing so, memory access requests for the memory address range, which would normally be directed to the active memory device, may instead be directed to the redundant memory device, thus enabling the active memory device to be tested (e.g., via writing and reading test data patterns to the active memory device) without interrupting system access to that memory address range.