We need to monitor many servers during our project.
Example: JMS, SNMP, POP3, Database, HTTP Server, Linux, Disk Space, Web Services, ..etc
The best tools we have are
www.opennms.org (Java, PostgreSQL ) (All OSs)
www.nagios.org (PHP, MySQL, Linux) (No Windows)
Still we can’t achieve few. We may need to write our own or Write some plugins to above tools.