There are disk device level replication like DRBD that mirrors disks synchronously across network. It's a generic solution for any disk mirroring. MySQL just

There are disk device level replication like DRBD that mirrors disks synchronously across network. It's a generic solution for any disk mirroring. MySQL just sits on top of it. Google probably got some super fast cross datacenter links to allow fast replication. Still the latency will be worse than local mirroring for synchronously replication.