In some business environments or homelabs it may be necessary to shutdown a vSAN cluster entirely.
VMware has a proper procedure outlined on the documents site.
Shutting Down and Restarting the vSAN Cluster (vmware.com)
Once you have completed your maintenance tasks and fire everything up, you may be startled when you login to each of the hosts and attempt to verify your VMs....
They will probably all display as an "INVALID" status with the GUID Path in the "name" field.
This message certainly caught one of my peers off guard during a recent datacenter update. That quick rush of butterflies in your gut that tells you all of your data is now corrupt.
However, I quickly reassured him that nothing was lost and the issue was simply that all of the hosts were still in maintenance mode.
When the vSAN nodes are in maintenance mode after a reboot, none of the stats are correct since none of the vSAN components are allowed to work together.
If you have powered on all of the vSAN nodes in the cluster and waited a sufficient amount of time for all the vSAN nodes to communicate, the remediation is actually quite swift.
Remove all the Hosts from Maintenance mode.