Hi,
When upgrading the ESXi to 6.5 via bootable ISO, is there any backup/failover in case the upgrade fails?
Where is the current configuration stored? (How does the upgraded ESXi gets the configuration)
Can the cluster have a mix of ESXi versions running at the same time until all the hosts are upgraded? (Hosts form a vSAN datastore)
Any specific checks post upgrade to confirm functionality?