Example implementations relate to managing data on a memory module. Data may be transferred between a first NVM and a second NVM on a memory module. The second NVM may have a higher memory capacity and a longer access latency than the first NVM. A mapping between a first address and a second address may be stored in an NVM on the memory module. The first address may refer to a location at which data is stored in the first NVM. The second address may refer to a location, in the second NVM, from which the data was copied.