Put a host in maintenance - Will it auomatically move VMs?

Dear All,

We have a cluster with 4 hosts and we would like now to upgrade each host from ESXi 5.50 to ESXi 6.0. I understand that we will need to put the host in maintenance mode. Will it automatically move the VMs to the other hosts? I have read DRS is needed. I see our hosts are license for Vmotion and HA. We have license from Vsphere standard.

Does it mean in our case I would need to manually move first the VMs before the host can go into maintenance mode? In case the Vsphere will do the job, would the VMs automatically distribute to the other 3 hosts according to the resources available?

Thanks,

Edy