Add fixes from review

Fixes #6761
This commit is contained in:
DeDe Morton 2017-03-01 14:19:26 -08:00
parent ebbf36f75f
commit da6099b2f1

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@ -21,19 +21,19 @@ persistent queues to buffer events on disk and remove the message broker.
In summary, the benefits of enabling persistent queues are as follows:
* Provides protection from in-flight message loss when the Logstash process is abnormally terminated.
* Absorbs bursts of events without needing an external buffering mechanism like Redis or Apache Kafka.
* Provides an at-least-once message delivery guarantee. If Logstash is restarted while events are
in-flight, Logstash will attempt to deliver messages stored in the persistent queue until delivery
succeeds at least once. In other words, messages stored in the persistent queue may be duplicated, but
not lost.
* Absorbs bursts of events without needing an external buffering mechanism like
Redis or Apache Kafka.
* Provides an at-least-once delivery guarantee against message loss during
a normal shutdown as well as when Logstash is terminated abnormally. If Logstash
is restarted while events are in-flight, Logstash will attempt to deliver
messages stored in the persistent queue until delivery succeeds at least once.
[[persistent-queues-limitations]]
==== Limitations of Persistent Queues
The following are problems not solved by the persistent queue feature:
* Input plugins that do not use a request-response protocol cannot be protected from data loss. For example: tcp, udp, zeromq push+pull, and many other inputs do not have a mechanism to acknowledge receipt to the sender. Plugins such as beats and http, which *do* have a acknowledgement capability, are well protected by this queue.
* Input plugins that do not use a request-response protocol cannot be protected from data loss. For example: tcp, udp, zeromq push+pull, and many other inputs do not have a mechanism to acknowledge receipt to the sender. Plugins such as beats and http, which *do* have an acknowledgement capability, are well protected by this queue.
* It does not handle permanent machine failures such as disk corruption, disk failure, and machine loss. The data persisted to disk is not replicated.
[[persistent-queues-architecture]]