Split Brain
In plain terms
When a cluster splits and multiple nodes act as leader.
Going deeper
Split-brain occurs when a network partition makes separated groups each think they're in charge, risking conflicting changes. It's a dangerous failure mode.
Under the hood
Prevented by quorum requirements and fencing; can cause data divergence and corruption if unhandled.
Examples
Cluster failures, quorum, fencing, leader election, data divergence.
Think of it like...
Like a company splitting into two factions each believing it's the real headquarters.