Two Switches, One Crown
The server-farm switch stack is the ground every service stands on. When an IRF fabric splits, two switches wake up believing they are the same device — same identity, same addresses — and the core no longer knows where anything lives.
[contact]ARP flapping at the core. Server-farm reachability degrading intermittently across sites — no pattern, no clean failure.
[recon]Traced duplicate MACs back to the farm stack: an IRF split-brain. Two masters fighting for one identity.
[assault]Isolated the stack members and re-established IRF roles — one control plane, one king.
[verify]Watched MAC and ARP convergence at the core until the tables went quiet and stayed quiet.
[aftermath]Stable server farm — and monitoring that makes the next split announce itself before users do.