Synchronization architectures, methods, systems, and computer readable media are described. In one embodiment, a synchronization session is initiated between a first data processing system and a second data processing system. The synchronization session includes at least a first portion and a second portion. The first data processing system performs the first portion of the synchronization session. The first data processing system receives a sync anchor checkpoint. The sync anchor checkpoint indicates to the second data processing system that the first portion of the synchronization session is complete before the second portion is complete. In one embodiment, the first data processing system determines that the synchronization session is in a failure state. The first data processing system transmits the sync anchor checkpoint to the second data processing system. The second portion of the synchronization session is performed.