有哪些工具可用于衡量企业基于Web的系统的“健康状况”？

I assist in maintaining an enterprise web-based system (programmed in J2EE, but this is a more general question) and I'd like to know: what good tools are out there to measure the "health" of an enterprise system? For instance, tools to check memory space on servers, check the status of batch runs, the number of records processed in a certain amount of time, etc?I assist in maintaining an enterprise web-based