When migrate VMs, something needs to be aware

1.       Hot migration only available with ESX V3.5 or later version;

2.       Any snapshot, dummy network or raw mapped drivers will cause migration failed (move them and re-add them back is the simplest way to do that)

3.       Migrate VMs between datastores, always make sure the host can access both datastores

4.       Migrate VMs between hosts with different CPU speed, need cold migration and have to set the power on option to menu and confirm it after migration while it powers on.

It also happens when you try to upgrade ESX host or apply the hot fix for ESX.

(to be continue…)