There are quite a few SO answers with details about actor mechanisms and also in docs, I can point you a few:
This one does not exactly answer your question, but I described a bit how the locking works: Start a thread inside an Azure Service Fabric actor?
Q: Is there any time-out mechanism, and if so is it somehow configurable?
yes, there is a timeout, I have answered here: Acquisition of turn based concurrency lock for actor '{actorName}' timed out after {time}
The configuration docs are located in here
Q: What happens if node where actor is located crashes, would client receives immediate error, or ActorProxy somehow handles this situation and redirects call to newly created instance of Actor on healthy node?
Generally there is always a replica available when one replica goes down, new requests will start moving to the new replica when SF promotes a secondary replica to Primary.
Regarding the communication, by default, SF Actors use .Net Remoting for communication the same way as the reliable services, the behaviour is described very well in here, In summary, it retries transient failures, if the client can't connect to the service(Actor) it will retry until it reaches the connection timeout.
From the docs:
The service proxy handles all failover exceptions for the service partition it is created for. It re-resolves the endpoints if there are failover exceptions (non-transient exceptions) and retries the call with the correct endpoint. The number of retries for failover exceptions is indefinite. If transient exceptions occur, the proxy retries the call.
The Actor docs, has more info, in summary there are two points to keep in mind:
- Message delivery is best effort.
- Actors may receive duplicate messages from the same client.
That means, in case a transient failure occurs while delivering a message, it will retry, even though the message has been already delivered, causing duplicate messages.
