What is Power | Total Energy (Wh) metric?

[Gabrie1]

Hi,

In vROPs I’m looking at power usage of our ESXi hosts. When opening the metrics of a host, I see Power | Total Energy (Wh). For a host this gives me values like 32.7458 Wh.

However, in vCenter via monitor -> performance ->advanced, when opening the “Power” “Usage” chart, I get values around 390 Watt. In vCenter from Monitor hardware health, I get the metric “System Board 1 POWER_USAGE” with values of around 360 Watts. And back to vROPs looking at the info from the hardware blade underneath the ESXi host in vROPs, I have a metric Power | Consumed Power (Watts) that shows values around 370 Watt.

The values of 360 Watt and more are fine with me, but I can’t figure out what the vROPs metric “Power | Total Energy (Wh)” is and why this is so low. Do I need to convert this value in someway to get near the 360Watt and more?

The docs only say: Total energy used. Formula: Total Energy (Wh) = Sum(Power|Energy (Joule))/3600

https://docs.vmware.com/en/vRealize-Operations/8.6/com.vmware.vcom.metrics.doc/GUID-06199D37-FD3E-4A15-A24F-6328DC0D1F98.html

[souzader]

Hi  

 

In vROps, we are computing Watt-hour (Wh) which is different than Watts (W). We use Watt-hour since it is the unit of energy and easy to calculate the cost as electricity cost is based on KWh ( Kilo Watt-hour)
So vROps collects Energy metrics (in Joules) from vCenter and calculate Watt-hour (Wh) using the formula : Total Power ( in Wh) = Energy (In Joules) / 3600
This is based on the conversion that 1 Joule = 0.000277778 Watt-hour OR 1/3600 Watt-hour

 

So in case of vCenter the granularity is 20 seconds with unit Joules ( each data point means for the past 20 seconds how many Joule the server consumed ) so when calculating in terms of W it is J/20. As it is calculated for 20 seconds and that is one data point.

In case of vROPS the metric is 300 second average, not instantaneous.

For example:
vCenter will give : 120 W (for 20 seconds x 15 data points)
And accordingly in vROps: 120 / 12 = 10 Wh (as this data is for 5 minutes so divide by 12 to make in Wh)

This what you see in the graph.

The idea behind the metric is to sum them up over time, not to show the consumption at any given second (which is not useful)

 

https://www.vmwareopsguide.com/dashboards/chapter-9-other-dashboards/3.9.1-green-operations/