Cassandra: Understanding Hinted Handoff
Jonathan Ellis explains hinted handoff and its implications on consistency, availability, and performance:
A hinted write does not count towards ConsistencyLevel requirements of
ONE,QUORUM, orALL. If insufficient replica targets are alive to sastisfy a requested ConsistencyLevel,UnavailableExceptionwill be thrown with or without Hinted Handoff. (This is an important difference from Dynamo’s replication model; Cassandra does not default to sloppy quorum. But, see “Extreme write availability” below.)
Original title and link: Cassandra: Understanding Hinted Handoff (NoSQL databases © myNoSQL)
via: http://www.datastax.com/dev/blog/understanding-hinted-handoff