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You don't understand Raft. Quorum has to fsync for commit
by jimsimmons 5y ago
You don't understand Raft. Quorum has to fsync for commit
- rubiquity 5y agoIt reads like you and GP are talking about two different things. You’re talking about Raft specifics and the GP seems to be talking about a Vertical Paxos like setup where Raft is used for configuration and the data path uses another replication algorithm such as Primary-Backup or Chain Replication.
- jimsimmons 5y agoHmmm that sorta makes sense I guess. Sorta because raft is a replication algorithm. If you don't use raft in datapath you don't get any of its guarantees
- rubiquity 5y agoMost data paths don't need consensus for replication. You can implement ACID Transactions on top of many other replication algorithms for example. Ultimately the choice comes down to read/write ratios. Chain Replication has much better read throughout than Paxos and Raft.
- jimsimmons 5y agoI see. What's the catch though. Sounds like free lunch. Is there some gotcha with partition tolerance?
- rubiquity 5y agoIt’s the case of 2F+1 versus F+1. Paxos/Raft offer fault tolerance where as other replication algorithms don’t. If you have a node failure in Primary-Backup or Chain for example you need to reconfigure before committing more writes. However in practice and certain environments reconfiguration can be faster than or the same as a leader failure in Paxos that requires running Phase 1 again.
- jimsimmons 5y agoGot it, makes sense. To the extent this can be formalized, I feel this is a much better alternative than consensus based approaches