This document compares message and metric management solutions like Fluentd and Logstash. It discusses how these solutions can collect, store, visualize, and alert on log and metric data from heterogeneous environments. While commercial solutions like Splunk are very expensive, open source solutions like Fluentd, Logstash, Elasticsearch, and Kibana provide similar functionality through various "bricks" or components at no cost. The document analyzes key differences between Fluentd and Logstash, such as their configuration, buffering approaches, high availability features, and plugin ecosystems.