4 ms·
> hence you need to query _all_ the nodes or can end up in a split-brain situation and lose consistency (or availability if you choose to down the system or a p
by toolslive 6y ago
> hence you need to query _all_ the nodes or can end up in a split-brain situation and lose consistency (or availability if you choose to down the system or a part of the system).
No.Depending on the type of consensus algorithm you can get away with reading from a majority or nodes or even less: for example in a Multipaxos system you just read from the master.
- valenterry 6y agoThen what happens in case of network partitions?
- benlivengood 6y agoOne side of the partition has quorum and the other does not. Processing keeps happening on the partition with quorum. A practical example I worked on is Google's Photon; multi-region logjoining with Paxos for consistency. When the network caused a region to become unavailable all the logjoining work happened in the other regions. Resources were provisioned for enough excess capacity to run at full speed in the case of a single region failure and the N-region processing allowed the redundancy cost to be as low as 100%/N overhead.
- valenterry 6y agoYou are describing the case where there are 2 groups that are isolated/partitioned. But what if there are more than 2?