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Assuming I have a server setup where a quorum vote is always satisfied, how likely will a Split Brain situation occur with Galera? My understanding is Galera does its best to avoid it, but does that mean there's 0 chance of it ever happening if the servers and MySQL/MariaDB processes never fail?

If it's a real possibility, is there a best practice for proper recovery?

Phil
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1 Answers1

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I assume you have a 3-node system with no weightings and the nodes are in separate geographical locations?

Split brain usually happens when these two things occur:

  1. One node dies, and before you can get it repaired,...
  2. The network between the two other nodes dies. Now neither of those nodes will accept writes because neither has a quorum.

Hence no "split brain", but instead a read-only system.

The simple answer is that "quorum" prevents "split brain".

Rick James
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