{CodeRoyale}
All challenges
Multiple ChoiceIntermediate 45s

Fencing tokens

How do fencing tokens prevent a 'zombie' leader (one that paused then resumed thinking it is still leader) from corrupting data?
Options
  1. 1They encrypt the leader's writes with a per-term secret key so that a stale leader can no longer produce any valid signed writes at all
  2. 2Each leadership term gets a monotonically increasing token; storage rejects writes with a token lower than the latest seen, so the stale leader's writes are refused
  3. 3They reduce the leader's lease TTL significantly so that it must renew its lease far more frequently in order to stay the recognized leader
  4. 4They force the leader to step down immediately whenever it resumes after a long pause, a GC stall, a network blip, or a partition
system-designconsensusleader-election

Think you can answer under pressure?

Get matched and answer live questions in 3-minute 1v1 battles. Elo ranking, badge tiers and bragging rights on the line.

Play this in a 3-minute battle