Could anyone share what they use for performance thresholds on a VMAX running FAST VP?  Throughout our POC and now in production i'm seeing the BE Directors with 45-75% busy % across the array.  According to the definition this doesn't seem like it's neccessarily a bad thing

#% busy

100 - %idle This metric is available only for Fibre Channel directors.

Is this a measure of CPU?  I thought the CPU's for front end and back end were shared in the matrix? 

The % busy on the ports is under 5 during this time. 

What is everyone else seeing on their array's running FAST VP?