A memory system may include: a plurality of memory devices each including a user area and an over-provisioning area (OP area); and a controller configured for controlling the plurality of memory devices, wherein the controller includes: a detection circuit configured for detecting a defective memory device among the plurality of memory devices; a selection circuit configured for selecting an available memory device excluding the defective memory device among the plurality of memory devices; and a processor configured for moving target data stored in the defective memory device into the OP area of the available memory device.