Re: Wasn't Split Brain solved 30 years ago?
Yes, VMS cluster, Solaris cluster, Veritas cluster, they all do that for local HA, and it works. Disk vendors like EMC and HDS can also do it for their distributed storage.
Don't forget Tandem NonStop systems, which distributed the whole kit and caboodle (CPUs, disks, disk controllers) over geographic distances as a networked set of up to 16 nodes, each containing between 2 and 16 CPUs with all hardware duplicated and hot-pluggable. The whole distributed system was fault tolerant by design with automatic fail-over for all components. Result: 99.99% up time.
... and that was early '80s technology, so there's really no excuse for current systems supporting worldwide 24x7 services to offer less guaranteed availability than was available in 1984.