Requirements

Let’s sum up what we want our monitoring system to do for us:

Monitor critical local processes on a server for crashes.
Monitor any anomalies in the use of CPU/memory/disk/network bandwidth by a process on a server.
Monitor overall server health, such as CPU, memory, disk, network bandwidth, average load, and so on.
Monitor hardware component faults on a server, such as memory failures, failing or slowing disk, and so on.
Monitor the server’s ability to reach out-of-server critical services, such as network file systems ...