News for hackers. Stuff that matters.

A comment on S3 Strong Consistency. Parent comment

Re:S3 Strong Consistency by toolslive on Wednesday December 02, 2020 @02:59AM (#25274162)
> 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.

[ Parent | on HN ]
Re:S3 Strong Consistency by valenterry on Wednesday December 02, 2020 @10:19AM (#25277073)
Then what happens in case of network partitions?
[ Parent | on HN ]
Re:S3 Strong Consistency by benlivengood on Wednesday December 02, 2020 @02:28PM (#25280392)
One 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.

[ Parent | on HN ]
Re:S3 Strong Consistency by valenterry on Wednesday December 02, 2020 @09:40PM (#25284627)
You are describing the case where there are 2 groups that are isolated/partitioned.

But what if there are more than 2?

[ Parent | on HN ]