After adding a new host to an HA enabled cluster in vCenter, an alert in seen on the ESXi host., "The number of vSphere HA heartbeat datastores for this host is 0, which is less than required: 2
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After adding a new host to an HA enabled cluster in vCenter, an alert in seen on the ESXi host., "The number of vSphere HA heartbeat datastores for this host is 0, which is less than required: 2

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Article ID: 415891

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Updated On:

Products

VMware vSphere ESXi

Issue/Introduction

  • After adding a new host to an  HA enabled cluster in vCenter, an alert in seen on the ESXi host., "The number of vSphere HA heartbeat datastores for this host is 0, which is less than required: 2
  • If we go to Configure tab and under Services and click on vSphere Availability, expand Datastore for Heartbeating, we can see that datastores are already configured.
  • If we check the ESXi host and the list of datastores, these datastores would be listed under host's Datastore tab.

Environment

  • vSphere 7.x
  • vSphere 8.x
  • vSphere 9.x

Cause

  • The datastores configured for heart beating are connected to the newly added ESXi but were not mounted.
    • Note:
      • Ideally, if a LUN is presented to datastore a rescan of VMFS volumes on the host should mount the datastores automatically. Scenarios like LUN being detected as a snapshot LUN or any underlying storage issue can lead to such issue where datastore is not mounted automatically.
      • Before proceeding ahead with the resolution steps, kindly ensure that this is not a snapshot LUN.
        • To list the volumes detected as snapshots, run this command:

          • esxcli storage vmfs snapshot list


            You see output similar to:

            ########-########-####-############


            Volume Name: VMFS_1
            VMFS UUID:            ########-########-####-############
            Can mount: true
            Reason for un-mountability:
            Can resignature: true
            Reason for non-resignaturability:
            Unresolved Extent Count: 1

  • To validate from GUI, In the vSphere Client, go to Home > Storage, select the desired datastore from the left panel, click the Configure tab, choose Connectivity and Multipathing, and check the Status column for each listed ESXi host. The newly added host would not be present.
  • To validate from CLI, take an SSH session to the ESXi host and check the output of below command:
    • esxcli storage filesystem list
      • With the datastore name, the mounted flag would be false 

Resolution

  • Mount the datastores:

    • Log in to the vSphere Client and navigate to your vCenter Server.

    • Go to Storage from the Home menu.

    • Select the datastore you want to mount.

    • Click the Hosts tab, then select Mount Datastore to Additional Hosts (or Mount to Hosts depending on the version).

    • In the wizard, select the ESXi hosts you want to mount the datastore to and click Next.

    • Review the selections and click Finish.

    • Re-enable HA on the cluster or just reconfigure HA on the ESXi host.

Note: If there are any issues with mounting the datastore, kindly open a support request with us.

 

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