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Why would you ever want to do distributed locking when you can do MVCC via eg vector clocks, possibly with cryptographic signatures?

If you want to acquire some shared resource, then elect an owner for that resource.

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If you want to do mutual exclusion using distributed locking then you end up in a painful place (as the article points out). In general you can't distinguish between a process that is running really slowly and a process that is dead. So when confronted with a non-responsive lock owner you end up with two unpleasant options: 1) Assume the lock owner is alive and don't do anything. This approach guarantees mutual exclusion but isn't especially useful because it gets stuck when things die. 2) Assume the lock owner is dead and take the lock. This doesn't guarantee mutual exclusion but "probably" works if you make the timeout "long enough." This can work correctly if you have a realtime system which will monitor the lock owner and kill the owner if the lease on the shared resource expires (this would probably require a special hardware/OS/programming language stack).

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