Hi,
yes, it have great use of broker /buffer tool for log analysis and it is also with new version of Log stash and Elasticsearch.
you can use Redis or kafka or RabitMQ as buffer /broker and using of it all depends on your need.
Kafka and Redis. Both tools provide the functionality of data streaming and aggregation in their own respective ways.
A broker acts as a queue from which one or more Logstash instances can pull events. It' is also useful for load balancing requests and also acts as a buffer when there are lots of incoming events.
for more refer below link: