Re:KIP-500: Replace ZooKeeper with a Self-Managed Metadata Q...
by hinkley on Friday August 02, 2019 @06:45PM
(#20597288)
Raft is not going to be the last consensus protocol.
If that assertion is true, then the replacement will exist because something in Raft is difficult or impossible to do. In which case consensus is hard, for some quantity of hard.
The one that's most obvious to me is that Raft violates one of the 8 Fallacies of Network Computing: the network is homogeneous.
The star topology of messages means that some messages - identical messages with different destinations - will be competing for bandwidth. It also means electing the slowest machine on the longest network link is probably a bad idea. I've certainly heard of this sort of problem happening.
If that assertion is true, then the replacement will exist because something in Raft is difficult or impossible to do. In which case consensus is hard, for some quantity of hard.
The one that's most obvious to me is that Raft violates one of the 8 Fallacies of Network Computing: the network is homogeneous.
The star topology of messages means that some messages - identical messages with different destinations - will be competing for bandwidth. It also means electing the slowest machine on the longest network link is probably a bad idea. I've certainly heard of this sort of problem happening.