1808 Cluster AutoBalancer event invoked when host resources not taxed


I have a two-node Hyper-V HA cluster running on Server 2016.  This is in a test environment with very little load on it now.  There are a total of 5 VMs (all running server 2016), with three (DB1, DB2, and App) on node1 and two on node2. 
I have not set any preferred nodes for the VMs, and Balancer settings are default for the cluster.  The three VMs on node1 communicate with each other mode, which is why they are together.  The two hosts are identical with 16 cores (2 sockets) and
64GB of RAM each.  Hyperthreading is disabled and virtualization is enabled in the BIOS.  Each VM in the cluster has 1 vCPU and 4GB of RAM, with the exception of DB1, which has 2 vCPUs.

The cluster node assignments have been in this configuration for a while, working fine.  I’ve always been able to live migrate them between the nodes without issue when needed for maintenance, but they are always put back on their respective nodes for
normal operation.

A couple days ago, McAfee on App went nuts and consumed a lot of CPU for a sustained period.  This appears to have been the catalyst for
the 1808 event and the cluster moving both that server and DB2 to the other node.  We were able to quiet down McAfee later so it wouldn’t consume so much CPU on App, but didn’t see anything on DB2 that would increase utilization.

Knowing all that, my question is: Why would the cluster move a server from one node to the other when the physical resources of the original node it was on were not even close to hitting any limits?  I could have had all five VMs on one node, with a
total of 6 procs and 20GB of RAM, and if all the VMs combined were using all of their virtual resources it would still be much lower than what the physical host has.  So, to ask my question in another way… Shouldn’t the reason to trigger an AutoBalancer
event be caused by collective Host utilization and not that of the VMs on them per se?

Please explain why this VM moved on it’s own when host resources were not taxed.

Thank You

Read full post . . . .

Go Que Newsroom Categories

Fatal error: Allowed memory size of 67108864 bytes exhausted (tried to allocate 40 bytes) in /home/content/36/8658336/html/goquecom/wp-includes/wp-db.php on line 1995