| 摘要 |
The invention provides a method and system for persistent and reliable delivery of event messages. Those parts of the system responsible for delivering event messages are able to persistently maintain those event messages until the intended recipient of the event message confirms delivery of those event messages. Those parts of the system responsible for recovering from system crashes and other system errors are able to persistently maintain those event messages until delivery, even after recovery from system crashes or other system errors. The system includes a set of event message producers, and maintains an event-indication queue of those event messages provided by the event producers using a set of pre-allocated resources. An event-distribution engine distributes event messages to intended recipients and, after having received confirmation that the event messages were received, removes them from the event-indication queue. Recipients of event messages receive the event messages, acknowledge their receipt thereof, and might take action in response to the event message. The system includes persistent memory, initialization memory, and recipient persistent memories, and provides upon recovery from system crashes or other system error, an ability to replay event messages recorded in those memories, to re-present them as event messages. A cluster of file servers collectively forming a highly-available system shares persistent memories, so that upon a system crash or other system error, at least one other file server has a record of those event messages.
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