can't wait to read the white paper
Data is spread out across transaction and storage nodes and it always available. When network partitions occur NuoDB continues offering services via the most available and healthy segment while the other segments provide a consistent read-only snapshot while awaiting reconnection at which point they will synchronize with their counterparts. Clients can simply reconnect to the active partition of the cluster to continue processing updates.
I'm not sure how they can ensure that network partitions only occur between fully replicated sets (i.e. how can all the data be available in all locations?)