How you decide whether an event happened before another event in the absence of any shared clock
- The quorum technique for ensuring single-copy serializability
- different fault-tolerance properties
- How eventual consistency, and other techniques, seek to avoid this tension at the cost of weaker guarantees about system behaviour
- Leader election
- Consistent snapshotting
- Consensus
- 2PC
- Paxos
- Distributed state machine replication