Inconsistency between the PVDC GHZ Capacity and the backend Cluster GHZ metrics

Products

• VCF Operations/Automation (formerly VMware Aria Suite)

Issue/Introduction

Assistance in understanding the capacity of a PVDC (Provider VDC) versus the backend cluster capacity in a Cloud Director environment.

Environment

Aria Operations 8.x

VMware Cloud Director 10.x

Resolution

"CPU|Total Capacity (MHZ)" on the Cluster Compute Resource object shows the total amount of CPU resources of all hosts in the cluster.

"CPU|Total (MHZ)" on PVDC, does not show the "Total Capacity" as mentioned on the previous line but is instead calculated as follows:

Total Reservation Capacity - Used Reservation by vCLS 

Note: The values for the calculation above can be found in the vCenter UI by selecting the related Cluster on the tab: Monitor >> CPU

The same value can then be seen in the VCD UI as "Reservation Committed"  on  PVDC object >> Configure >> Metrics

 

"CPU|Total Capacity (MHZ)" metric on the Cluster Compute Resource:

"CPU|Total (MHZ)" metric on related PVDC:

Calculation for "CPU|Total (MHZ)" on PVDC:

"Reservation Committed"  on the PVDC object in VCD:

Additional Information

"CPU|Total (MHZ)" on PVDC object in Aria Operations does not take vSphere HA and Buffers into account so this metric may not be suitable for capacity planning.

NOTE: There will also be a discrepancy between "CPU|Total (MHZ)" on the PVDC object and "CPU|Demand|Usable Capacity after HA and Buffer (GHz)" on the Cluster Compute Resource object, as "CPU|Total (MHZ)" on the PVDC object does not take the clusters HA and Buffer reservation into account. See related images below:

Cluster Configuration|vSphere HA|Admission Control Policy|CPU Failover Resources Percent (%) on the Cluster Compute Resource:

CPU|Demand|Usable Capacity after HA and Buffer (GHz) on the Cluster Compute Resource: