[iheartmemcache]

Oracle has a distributed transaction system that'll work cross-country, but I can't find the details. It's basically a complete rip-off of the OpenVMS implementation from the late 70s (or whenever all those VAX/VMSstations came out - post PDP), no surprises there, and it costs an insane amount just for that functionality (separate from RAC), but it works really well. I'm trying to find the docs since it's been more than half a decade since I used it but [1] is the closest I can get (and that's certainly not it, though RAC does it's job quite well also and that page is worth a read if only for exposing yourself to time-tested transactional models.) It might be HA-NFS over ACFS but that doesn't seem quite right to me. Anyways, read section 5 of this[2] Oracle doc, to have a master-class on maintaining database integrity across the datacenter or across the country. I've used a litany of DBs and I think I wouldn't pick anything made in the last 10 years for my primary store other than Datomic (which I've beaten into the ground as hard as I could and it took my abuse) and or maybeeee VoltDB (if only because Stonebraker is DJB-level smart).

[1] http://docs.oracle.com/cd/B28359_01/server.111/b28318/consis...