The architecture of a typical MySQL Enterprise Monitor installation is shown in the following figure:
MySQL Enterprise Monitor has the following components:
MySQL Enterprise Monitor Agent monitors the MySQL instances and hosts, and collects data according to a defined schedule. The collection data is sent to MySQL Enterprise Service Manager for analysis and presentation. MySQL Enterprise Monitor Agent is typically installed on the same host as the monitored server.
MySQL Enterprise Service Manager analyzes, stores and presents the data collected by the agent. MySQL Enterprise Service Manager also contains a built-in agent which is used to monitor the repository.
MySQL Enterprise Monitor Proxy and Aggregator intercepts queries as they are transmitted from client applications to the monitored MySQL instance and transmits them to the MySQL Enterprise Service Manager for analysis by the Query Analyzer.
It is also possible to perform what is called an Agent-less installation, where the Agent is not installed on the host machines, and all monitoring is done by MySQL Enterprise Service Manager's built-in Agent.
For performance reasons, the agent-less installation is not recommended for monitoring large implementations. It is useful for testing, or very small-scale implementations. It is strongly recommended to install an agent on each host.