Eventual Consistency (cont)
If different nodes have different versions of data
- conflicts arise, and need to be resolved (when noticed)
- need to decide which node has "the right value"
Levels of consistency (from Cassandra system)
- ONE: at least one node has committed change (weakest)
- QUORUM: at least half nodes holding data have committed
- ALL: changes propagated to all copies (strongest)
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