After a planned power outage, an administrator decided to restart the vSAN cluster manually.

This is the sequence of steps recommended by VMware for manually restarting the vSAN cluster after a planned power outage. The steps are as follows:

Enable cluster member updates from vCenter Server only on one ESXi host. This will allow the host to receive the latest cluster membership information from vCenter Server and avoid any conflicts or inconsistencies with other hosts. The command to enable cluster member updates is esxcfg-advcfg -s 1 /VSAN/IgnoreClusterMemberListUpdates.

Run the python reboot helper script only on one ESXi host to recover the cluster. This will prepare the cluster for a manual restart by partitioning the cluster and ensuring that all hosts have consistent metadata. The command to run the python reboot helper script is python /usr/lib/vmware/vsan/bin/reboot_helper.py prepare.

Exit all hosts from maintenance mode. This will allow the hosts to resume normal operations and join the vSAN cluster. The command to exit maintenance mode is esxcli system maintenanceMode set -e false.

The other options are incorrect for the following reasons:

B, exit all hosts from maintenance mode, run the python reboot helper script only on one ESXi host to recover the cluster, and enable cluster member updates from vCenter Server on all ESXi hosts, is incorrect because exiting all hosts from maintenance mode before running the python reboot helper script can cause data inconsistency or corruption, as the hosts may not have the latest metadata or cluster membership information. Enabling cluster member updates from vCenter Server on all ESXi hosts is also unnecessary and can cause conflicts or inconsistencies with other hosts.

C, exit all hosts from maintenance mode, enable cluster member updates from vCenter Server only on one ESXi host, and run the python reboot helper script only on one ESXi host to recover the cluster, is incorrect because exiting all hosts from maintenance mode before running the python reboot helper script can cause data inconsistency or corruption, as the hosts may not have the latest metadata or cluster membership information.

D, enable cluster member updates from vCenter Server on all ESXi hosts, run the python reboot helper script on all ESXi hosts to recover the cluster, and exit all hosts from maintenance mode, is incorrect because enabling cluster member updates from vCenter Server on all ESXi hosts is unnecessary and can causeconflicts or inconsistencies with other hosts. Running the python reboot helper script on all ESXi hosts concurrently can also cause a race condition that can result in unexpected outcomes.

References:

Manually Shut Down and Restart the vSAN Cluster

Restart the vSAN Cluster