Hi, We're encountering some issues on one of our production clusters running oVirt 4.2. We've had an incident with the engine's database a few weeks back that we were able to recover from, however since then we've been having a bunch of weird issues, mostly around MACs. It started off with the engine being unable to find a free MAC when creating a VM, despite there being significantly less virtual interfaces (around 250) than the total number of MACs in the default pool (default configuration, so 65536 addresses) and escalated into creating duplicate MACs (despite the pool not allowing it) and now we can't even modify the pool or remove VMs (since deleting the attached vnics fail), so we're kinda stuck with a cluster that has running VMs which are fine as long as we don't touch them, but on which we can't create new VMs (or modify the existing ones). In the engine's log we can see that we've had an "Unable to initialize MAC pool due to existing duplicates (Failed with error MAC_POOL_INITIALIZATION_FAILED and code 5010)" error when we tried to reconfigure the pool this morning (see the full error stack here : https://pastebin.com/6bKMfbLn) and now whenever we try to delete a VM or reconfigure the pool we have a 'Pool for id="58ca604b-017d-0374-0220-00000000014e" does not exist' error (see the full error stack here: https://pastebin.com/Huy91iig), but, if we check the engine's mac_pool table we can see that it's there : engine=# select * from mac_pools; id | name | description | allow_duplicate_mac_addresses | default_pool --------------------------------------+---------+------------------+-------------------------------+-------------- 58ca604b-017d-0374-0220-00000000014e | Default | Default MAC pool | f | t (1 row) engine=# select * from mac_pool_ranges; mac_pool_id | from_mac | to_mac --------------------------------------+-------------------+------------------- 58ca604b-017d-0374-0220-00000000014e | 56:6f:1a:1a:00:00 | 56:6f:1a:1a:ff:ff (1 row) I found this bugzilla that seems to somehow apply https://bugzilla.redhat.com/show_bug.cgi?id=1554180 however I don't really know how to "reinitialize engine", especially considering that the mac pool was not configured to allow duplicate macs to begin with, and I've no idea what the impact of that reinitialization would be on the current VMs. I'm quite new to oVirt (only been using it for one year) so any help would be greatly appreciated.