HA error: "The number of heartbeat datastores for host is 1, which is less than required: 2"

Products

• VMware vCenter Server
• VMware vSphere ESXi

Issue/Introduction

While configuring vSphere High Availability (HA), there may be the error:

The number of heartbeat datastores for host is 1, which is less than required: 2

The above error can also occur if one of the two heartbeat datastores go offline due to underlying storage issues.

Environment

VMware vCenter Server 6.5.x
VMware vCenter Server 6.7.x
VMware vCenter Server 7.x
VMware vCenter Server 8.x

Cause

This alert triggers when lower than two shared datastores are designated or accessible for heartbeating. As of vSphere 6.0 and above, vSphere HA requires a minimum of two shared datastores accessible by all hosts within the cluster to handle datastore heartbeat monitoring.

• Log in to vCenter Server.
• Navigate to affected cluster > Configure > vSphere Availability.
• Expand Datastore for Heartbeating
• Verify that no datastores are configured

Confirm this by looking at the Heartbeat datastore configuration for the cluster in question and confirm that no datastores have been selected:

Resolution

 

To only disable the HA error message:

1. Log in to vCenter Server.
2. Right-click the cluster, click Settings.
3. Go to Configure tab, under Services click on vSphere Availability.
4. Click Edit vSphere HA in Edit Cluster Settings go to Advanced Options tab.
5. In the Option field type das.ignoreInsufficientHbDatastore, in the Value field type true. Click on ADD and click OK.
6. In vSphere Availability click on Edit for vSphere HA and toggle vSphere HA to disable HA and click OK.
7. Allow time for all the hosts in the cluster to be unconfigure vSphere HA.
8. In vSphere Availability the vSphere HA will be Turned OFF, To Turn ON, Click on Edit vSphere HA.
9. Enable vSphere HA by toggle and click OK. Wait for all the hosts to get vSphere HA configured.
10. Make sure vSphere HA is Turned ON state.

To resolve this issue:

Add at least two heartbeat datastore for HA monitoring to the vSphere Availability configuration.

1. Log in to vCenter Server.
2. Navigate to affected cluster > Configure > vSphere Availability.
3. Click Edit for vSphere HA and navigate to Heartbeat Datastores
4. Pick either Automatically select datastores accessible from the hosts or Use datastores from the specified list and complement automatically if needed
5. If Use datastores from the specified list and complement automatically if needed is selected, then select at least two datastores from the Available heartbeat datastores list below.

Then confirm the setting change.