Two rounds of voting: consensus vs 2PC
Two rounds of voting: consensus vs 2PC
Consensus
round 1: elect a leader
round 2: approve each entry
any node may start
a quorum reply is enough
one silent node is fine
2PC
round 1: prepare, vote
round 2: commit or abort
only the coordinator asks
EVERY voter must reply
one silence stalls everything
The verdict
the 2PC coordinator stays a single point of failure
unless hardened by consensus itself