vSAN Health Service - Cluster - Host assignments in Site Fault Domains

Products

• VMware vSAN

Issue/Introduction

This article introduces the new vSAN Skyline Health check 'Host assignments in Site Fault Domains' in vSAN 9.0 and provides details on why it might report the error and how to fix the error state.

Environment

VMware vSAN 9.0

Resolution

Q: What does the 'Host assignments in Site Fault Domains' check do? 

This check validates if all the hosts in a Stretched Compute Cluster are assigned to Site Fault Domains.

• For a Stretched Compute Only cluster, it is required every host in the cluster must be assigned to one of the two Site Fault Domains.

Q: What does it mean when it is in an error state?

If this check fails, it means there're host(s) in the cluster not being assigned to a Site Fault Domain. In a Stretched Compute cluster, workloads running on host(s) without proper site fault domain configuration may not achieve their best performance as the site affinity between the compute resource (provided by the stretched compute cluster) and the storage resource (provided by a remote vSAN cluster) cannot be realized.

Q: How does one troubleshoot and fix the error state?

Please follow the guidelines as below to fix the compliance issues.

1. For issue 'Host is not assigned to a Site Fault Domain', go to 'Cluster' → 'Configuration' → 'Fault Domains' page, add that host into one of the two Site Fault Domains.
2. For issue 'Host incompatible with Stretched Compute cluster', please either upgrade the host to ESXi 9.0 or above, or remove that host from the cluster.