Projections may vary significantly when extended by another day in vRealize Operations Manager 6.x

Products

• VMware Aria Suite

Issue/Introduction

Symptoms:

• Significant deviation can be observed when Projections are extended by another day and depending on the number of days being forecasted

Environment

VMware vRealize Operations Manager 6.5.x
VMware vRealize Operations Manager 6.6.x
VMware vRealize Operations Manager 6.4.x
VMware vRealize Operations Manager 6.3.x
VMware vRealize Operations Manager 6.2.x
VMware vRealize Operations Manager 6.1.x
VMware vRealize Operations Manager 6.0.x

Cause

Capacity trend calculations rely on the entirety of a resource metric history, and may deviate depending on the interval and number of data points requested by the UI.  

Example: A calculation which requests 10 data points from time A to B may not necessarily be a subset of a calculation requesting 11 data points from time A to B + 1.
The UI has a limitation on the number of points being drawn, and uses the requested time to get as close to the limit of points for the interval.

Resolution

This is expected behavior in vRealize Operations Manager 6.6.x and below.