When the number of nodes n is even, a majority requires (n/2 + 1) nodes. When there are two nodes, it requires two nodes in order to have a majority.
Tsz-Wo On Thu, Jul 14, 2022 at 10:07 AM Asad Awadia <[email protected]> wrote: > So that's the thing. Both have a majority. Since there are two 'clusters' > of 1 node each. There are only 2 nodes. ( i know should be odd) > > So both sides think they have majority right? What then? > > Regards, > Asad > > > On Thu., Jul. 14, 2022, 11:49 a.m. Tsz Wo Sze, <[email protected]> wrote: > >> Hi Asad, >> >> Raft uses majority for committing transactions. When two nodes are not >> aware of each other are both taking writes, at most one of them can get a >> majority. The one(s) without majority cannot commit any transactions. >> When these two nodes are merged, if one of them had the majority >> previously, the one without majority won't be voted as the leader so that >> its (non-committed) transactions will be dropped. >> >> For the details, please see the Raft paper >> https://raft.github.io/raft.pdf . It should be discussed in Section 5.4 >> Safety. >> >> Tsz-Wo >> >> >> >> On Thu, Jul 14, 2022 at 6:57 AM Asad Awadia <[email protected]> wrote: >> >>> Hello, >>> >>> How does ratis handle split brain? (Using the term counter?) >>> >>> That is two nodes are not aware of each other are both taking writes and >>> now are merged into one cluster with one leader. >>> >>> How are the writes reconciled? Whose work is overwritten? Or is the >>> cluster now in a bad state in need of manual intervention? >>> >>> Regards, >>> Asad >>> >>
