Sorry if this is not the correct place to enter this. Just a suggestions to add the Disk Q Length as a Filesystem metric. I find it to be one of the single best signs of hard drive congestion on Windows servers. Since different servers and even arrays within them will have differing performance levels the existing Disk Read/Write metrics don't provide a quick (and reliable alert source) metric of hard-disk to load performance, Disk Q Length does. Any chance of implementing something like this in the future?
in /pdk/examples/ of your HQ-Agent directory you will find a plugin io-device-all-plugin.xml which perfectly fits your needs. It's based on iostat and is able to print out various various hard drive metrics. Do you know how to deploy it ?