Described is memory system enabling memory mirroring in single write operations for the primary and backup data storage. The memory system utilizes a memory channel including one or more latency groups, with each latency group encompassing a number of memory modules that have the same signal timing to the controller. A primary copy and a backup copy of a data element can be written to two memory modules in the same latency group of the channel and in a single write operation. The buses of the channel may have the same trace length to each of the memory modules within a latency group.