[ovirt-users] unhappiness with ovirt engine after upgrading file server handling storage domain

Hi. I recently upgraded my oVirt infrastructure to the latest 4.1.1.8-1.el7.centos, which went smoothly. Thanks oVirt team! This morning, I upgraded my NFS file server which manages the storage domain. I stopped ovirt engine, did a yum update to bring the server from its older CentOS 7.2 release to CentOS 7.3, rebooted it, then restarted engine. At that point, engine was unhappy because our 4 virtualization hosts had a total of 30 VMs all waiting to reconnect to storage. The status of all the VMs went to unknown in engine. It took almost 2 hours before everything was completely normal again. It seems that the hosts were available long before engine updated status. I'm assuming it's better to restart engine when I know that NFS has resumed on all the 30 virtalized hosts. However, it's hard to know when that's happened, without trying to connect manually to all the hosts. Is there a way to warn engine that you're about to mess with the storage domain, and you don't want it to do anything drastic? Sort of like a "maintenance mode" for storage? I would hate for it to start trying to power off hosts via power management or migrate hosts when it just needs to wait a bit... Thanks! Jason.