This procedure describes how to unstretch a vSAN cluster which is stretched across two availability zones and convert it to a standard vSAN cluster.

As an example, we will consider a use case in which there two availability zones, AZ1 and AZ2, in two buildings in an office campus. Each availability zone has its own power supply and network. The management domain is on AZ1 and contains the default cluster, SDDC-Cluster1, which is stretched between AZ1 and AZ2. There are four ESXi hosts each in AZ1 and AZ2, which are categorized into the primary fault domain and secondary fault domain. This example unstretches the default cluster in the management domain and converts the stretched cluster to standard vSAN cluster.


You must have a stretched cluster.


  1. SSH in to the SDDC Manager VM using the vcf administrative user account.
  2. Enter su to switch to the root user and navigate to the /opt/vmware/sddc-support directory.
  3. Enter the following command:
    ./sos --unstretch-vsan --sc-cluster <CLUSTER NAME> --sc-domain <DOMAIN NAME> 
    Example input and response:
    root@sddc-manager [ /opt/vmware/sddc-support ]# ./sos --unstretch-vsan --sc-cluster SDDC-Cluster1 --sc-domain MGMT 
    Welcome to Supportability and Serviceability(SoS) utility!
    Logs : /var/log/vmware/vcf/sddc-support/stretchCluster-2019-02-21-07-36-18-66388
    Stretch Cluster operation log : /var/log/vmware/vcf/sddc-support/stretchCluster-2019-02-21-07-36-18-66388/sos.log
    Starting vSAN stretched cluster operations..
    vSAN un-stretch operation started..
    Api Response:{
      "taskId": "9c3b0975-be3c-42f2-8d1a-3d708c2c3263",
      "resourceId": "5f6cac74-6fbb-4570-b240-1a0ed5a54118",
      "resourceType": "ESXI",
      "state": "IN_PROGRESS",
      "description": "Un-Stretch vSAN Stretched Cluster - SDDC-Cluster1 in VMware Cloud Foundation",
      "timestamp": 1550734579412,
      "id": "9c3b0975-be3c-42f2-8d1a-3d708c2c3263"
  4. Monitor the state of the task in the SDDC Manager Dashboard.
    When the task completes, all the hosts from the AZ2 are removed from the cluster and cluster is converted to standard vSAN cluster.
  5. Validate that vSAN cluster operations are working correctly by logging in to the vSphere Web Client.
    1. Check the vSAN Health page.
      1. On the home page, click Host and Clusters and then select the vSAN cluster (SDDC-Cluster1 in our example).
      2. Click Monitor > vSAN > Health.
      3. Click Retest.
      4. Fix errors, if any.
    2. Check the vSAN Storage Policy page.
      1. On the home page, click Policies and Profiles > VM Storage Policies > vSAN Default Storage Policies .
      2. Select the policy associated with the vCenter Server for the vSAN cluster.
      3. Click Monitor > VMs and Virtual Disks.
      4. Click Refresh.
      5. Click Trigger VM storage policy compliance check .
      6. Check the Compliance Status column for each VM component.
      7. Fix errors, if any.