What is the best way to go about creating a derived metric from metrics readily available via existing plugins?
As an example, let's say I want a metric for total disk I/O time per interval computed from "Disk Service Time", "Disk Reads per Minute" and "Disk Writes per Minute" provided by the FileServerMount plugin:
Total time = DiskServiceTime * (DiskReadsPerMinute + DiskWritesPerMinute)
Any pointers on where to start looking are appreciated. Thanks!
