split-brain
jargonnetworkingcloudops culture
The cluster failure where partitioned nodes each believe they are the survivor, and both keep writing.
When the link between cluster members fails, each side may conclude the other is dead, promote itself, and accept writes; on reconnection the histories have diverged and someone's data must lose. Quorum rules, fencing (shoot the other node in the head), and witness nodes exist to make exactly one side win. Split-brain is the CAP theorem arriving in production, usually at night.