Memory system enabling memory mirroring in single write operations. The memory system includes a memory channel which can store duplicate copies of a data element into multiple locations in the memory channel. The multiple locations are disposed in different memory modules and have different propagation times with respect to a data signal transmitted from the memory controller. In a write operation, the relative timings of the chip select, command and address signals among the multiple locations are adjusted according to the data propagation delay. As a result, a data element can be written into the multiple locations responsive to a data signal transmitted from the memory controller in a single transmission event.