Running vCenter 6.7u3j and for our Citrix VMS we want to run a 1:1 vCPU:Core overcommit, therefore setting the DRS tot 1:1, fully automated and the aggressiveness to the default 3. All hosts have 56 logical processors, that is 28 cores and 2 CPUs.
When I now load my hosts with VMs and deliberately overload one of them with 2 vCPU's too many, DRS doesn't kick in to VMotion the VM. When I click RUN DRS I don't see any recommendations and if I leave it alone for more than 5min, there is no new recommendation either.
When I look at the DRS Balance, it says: Target: less than or equal to 0.126 Current: 0.036
Even after setting the aggressiveness to 4, the cluster remains balanced enough to not force a VMotion and maintain the 1:1 vCPU:Core ratio.Target: less than or equal to 0.063 Current: 0.039
Adding another VM with 4 vCPU to the first host, gives me 28 physical cores and 34 vCPU assigned on that host. The DRS balance changes to: Target: less than or equal to 0.063 Current: 0.047
It seems that even though 1:1 vCPU:Core is set, DRS still takes in account the CPU load for balancing the VMs. Is that correct?
I would have expected that even if the VMs were doing next to nothing in CPU and Memory load, DRS would try to maintain the 1:1 ratio. Is that an incorrect assumption?