Capacity tab for Cluster Compute Resource object shows unexpected values for Buffer or High availability - Aria Operations

Products

• VCF Operations/Automation (formerly VMware Aria Suite)
• VCF Operations

Issue/Introduction

This article explains how the values for "Buffer" and "High availability" are set on the Capacity tab of a Cluster Compute Resource object in Aria Operations.

 

Possible symptoms:

• Despite adding new ESXi hosts to a cluster, Aria Operations Capacity Remaining and Virtual Machine Remaining has not increased.
• Users may report that High Availability (HA) CPU allocation appears high (e.g., 50%) or remains static, even for large production clusters (e.g., 11+ hosts). This is typically observed when reviewing Usable Capacity or Capacity Remaining metrics, where the reported capacity does not match the expected physical capacity of the added hosts.

 

Example: High Availability failover capacity set in vCenter

 

Example: Capacity Buffer set in Aria Operations policy

Environment

Aria Operations 8.x
VCF Operations 9.0.x

Resolution

How the value (%) for Buffer is set:

1. In the Aria Operations UI browse to Configure >> Policies
2. Select the relevant policy and click "EDIT POLICY"
3. Then click on the Capacity pane.
4. Make sure that the "Cluster Compute Resource" is selected.
5. Scroll down to the "Capacity Buffer" section and click the lock icon to edit.
6. Edit the relevant values here to set/reset the Capacity Buffer values.
   
   Note: By default, only the demand model is used. You can turn the allocation model on in the active policy. See Allocation and Demand Model in Workload Optimization
   
   

How the value (%) for High Availability is set:

1. In the vCenter UI, open the Inventory and select the Cluster in question.
2. Open the Configure tab, then Services >> vSphere Availability
3. Click the EDIT button for vSphere HA
4. Then open the Admission Control tab
5. If the checkbox for "Override calculated failover capacity" is selected then Aria Operations will use the values defined for "Reserved failover capacity" specified as the Capacity tab values for High availability