There's a principle in distributed systems that you can't really count on clocks to be synchronized in a very large system but the thing about Parallel Sysplex is that it is not particularly scalable, it maxes out at 32 nodes but those nodes are pretty big -- the system overall is big enough for most of what the Fortune 500 does but tiny compared to Google, Facebook or a handful of really big systems. Sysplex revolves around distributed data structures similar to what Hazelcast provided in the beginning.