Hi *, I would greatly appreciate if anyone could help identifying some tweaks, if possible at all. This is a single control node environment with 19 compute nodes which are heavily used. It's still running on Pike and we won't be able to update until complete redeployment. I was able to improve the performance a lot by increasing the number of workers etc., but to me it seems the next bottleneck is rabbitmq. The rabbit process shows heavy CPU usage, almost constantly around 150% according to 'top' and I see heartbeat errors in the logs (e.g. cinder). Since there are so many config options I haven't touched them yet. Reading some of the tuning docs often refer to HA environments which is not the case here. I can paste some of the config snippets, maybe that already helps identifying anything: # nova.conf [oslo_messaging_rabbit] pool_max_size = 1600 pool_max_overflow = 1600 pool_timeout = 120 rpc_response_timeout = 120 rpc_conn_pool_size = 600