eventual consistency

Eventual consistency is a characteristic of distributed computing systems such that the value for a specific data item will, given enough time without updates, be consistent across all nodes. 

Accordingly, the value across all nodes will be consistent with the last update that was made -- eventually. Before enough time has elapsed without updates, however, the value may be inconsistent across multiple copies of the data. Eventual consistency is only acceptable for fault-tolerant applications.

In distributed computing environments, the CAP theorem postulates that it is impossible to simultaneously guarantee consistency, availability and partition tolerance (CAP) and that administrators have to select the two out of three that are most important to them. 

Eventual consistency is also known as optimistic replication.