vSAN Health Service - Stretched Cluster - Site Fault Domain configuration

Products

• VMware vSAN

Issue/Introduction

This article introduces the new vSAN Health Service check 'Site Fault Domain configuration' 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 'Site Fault Domain configuration' check do? 

This check validates the Site Fault Domain configurations are properly configured for a Stretched Compute cluster for optimal performance.

• For a Stretched Compute Only cluster, each of the 2 Site Fault Domains should have at least 1 host allocated.

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

If this check fails, it means the Stretched Compute cluster doesn't have a proper Site Fault Domain configuration, the site affinity between the cluster and the remote storage cluster may be compromised. As a result, workloads running in the cluster may not achieve their best performance.

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

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

1. Go to 'Cluster' → 'Configuration' → 'Fault Domains', for site fault domain with no host in it, add at least 1 host into the Site Fault Domain.

Alternatively, if the cluster no longer needs Site Fault Domains, follow the guidelines as below to fix the compliance issue:

1. Go to 'Cluster' → 'Configuration' → 'Fault Domains', click 'DISABLE STRETCHED COMPUTE CLUSTER' button and confirm by clicking 'DISABLE' to discard the Site Fault Domain configuration and convert the cluster back to a single site compute cluster.