Fencing Token ​

• The token in an acquire response A is a monotonically increasing u64 for that grant. It increases with every acquisition.
• On failover, the new active node continues from a value greater than the maximum token it received via replication (succession).
• If the protected resource validates token monotonicity, it can reject access from a client that woke up late after lease expiry with a lower token — keeping things safe even when the lock server itself isn't perfectly consistent.

See the How It Works page for a detailed discussion of cluster consistency.