Comparison
LinearisabilityvsStrong consistency
Linearisability
once one client has seen the new value, no other client is ever allowed to see the old one again.
The strongest single-object guarantee: operations appear to take effect instantaneously at some point between invocation and response, in real-time order. It is what makes a distributed lock or a leader election safe. It requires consensus and therefore a majority quorum on every operation, which is why it is expensive and reserved for coordination rather than bulk data.
Full entry →Strong consistency
every read is guaranteed to see the most recent committed write, so you never have to explain why the value went backwards.
A model where reads reflect all prior writes, typically by routing reads to the leader or requiring a quorum. It removes an entire class of "it works on my replica" bugs and costs latency, availability during failover, and cross-region round trips. Most systems need it for a small subset of their data and treat the rest as eventually consistent.
Full entry →