Hi, I have upgraded yesterday one of our ovirt environments from 4.2.8 to 4.3.8. We have a hosted engine, 25 hosts and about 150 VMs running there. After upgrading the cluster compatibility version from 4.2 to 4.3, I have seen a huge increase of CPU load on the engine VM. The engine had 4 cores (16GB mem) and never had load issues, but after the upgrade, the system has a load of 6 and more. I have increased the CPUs to 8, because working in the UI was impossible. I have noticed, that the load always increase, when I load the VM UI tab, where now all VMs have the orange triangle with pending changes: Custom compatibility version The problem I have, is, that I can't reboot now all VMs, maybe in the next 3 or 4 weeks. Working now with the UI is quite problematic, because of the slowness. The engine VM was already rebooted, but didn't solve the problem. What logs do you need and is there a workaround available? I have some more oVirt environments to upgrade, all with even more VMs. BR Florian