A memory system includes a memory device including a plurality of memory blocks; and a controller suitable for; storing user data corresponding to a write command received from a host, in the memory blocks, storing map data in response to storing of the user data, in the memory blocks, sorting map segments included in the map data, according to logical information of the user data, determining correlations for the memory blocks, through the map segments, and selecting source memory blocks among the memory blocks based on the determined correlations.