Eventual Consistency

This lecture takes note of the fact that all communication in a distributed system takes time—there is no instantaneous understanding of what a remote component is currently doing. We discuss this starting out from locally implemented strong consistency:

• by removing the blocking waiting for synchronization we see how consistency is weakened
• we discuss how an Actor is an island of consistency in a sea of inconsistency
• on the example of the Akka Cluster’s member state handling we demonstrate the function and value of CRDTs (conflict-free replicated data types)