ASK HN: Distributed Systems Snapshoting Theory vs Implementation

How are Distributed Snapshot algorithms (likes of Chandy Lamport) implemented in real world Distributed systems?

Wikipedia page for Snapshot Algorithms : http://en.wikipedia.org/wiki/Snapshot_algorithm

Can you name a system implementation (perhaps open source) which uses this / these class of algorithm?

How does this theory really translate to real world? What distributed snapshotting algorithms do real world systems use?