Configure a vSAN cluster that stretches across two geographic locations or sites.


  • Verify that you have a minimum of three hosts: one for the preferred site, one for the secondary site, and one host to act as a witness.
  • Verify that you have configured one host to serve as the witness host for the stretched cluster. Verify that the witness host is not part of the vSAN cluster, and that it has only one VMkernel adapter configured for vSAN data traffic.
  • Verify that the witness host is empty and does not contain any components. To configure an existing vSAN host as a witness host, first evacuate all data from the host and delete the disk group.


  1. Navigate to the vSAN cluster.
  2. Click the Configure tab.
  3. Under vSAN, click Fault Domains.
  4. Click the Stretched Cluster Configure button to open the stretched cluster configuration wizard.
  5. Select the hosts or the fault domain that you want to assign to the secondary domain and click >>.
    The hosts that are listed under the Preferred fault domain are in the preferred site.
  6. Click Next.
  7. Select a witness host that is not a member of the vSAN stretched cluster and click Next.
  8. Claim storage devices on the witness host and click Next.
    Claim storage devices on the witness host. Select one flash device for the cache tier, and one or more devices for the capacity tier.
  9. On the Ready to complete page, review the configuration and click Finish.