My expectation was that I will not be able to start any VM but that was NOT the case. MaxVcpusPerCore should solve the problem observed in previous two test because it should set vCPU / pCPU ratio per host which is much better from the predictability point of view. So vCPU / pCPU ratio is compliant per cluster but not per ESXi host as I have 8 vCPUs on single ESXi hosts having just 2 pCPUs. It is great, but it is worth to mention that VMs were started on single ESXi host even I have 4 ESXi hosts in DRS cluster. And I can really start only four VMs because each has 2 vCPUs so I can run up to 8 vCPUs in DRS cluster.Įrror when MaxVcpusPerClusterPct is set to 100 I have 4 node DRS cluster where each ESXi host has two cores (pCPUs), therefore I have 8 pCPUs available in the cluster. Let's set MaxVcpusPerClusterPct to 100% so we are saying to allow 1 : 1 vCPU / pCPU ratio. Well, it is a little bit misleading because it should be cluster-wide rule but it works as expected.Įrror when MaxVcpusPerClusterPct is set to 0 When I try to run VM I get the error "The total number of virtual CPUs present or requested in virtual machines' configuration has exceeded the limit on the host: 0". In other words, no VM can be running in the cluster. Let's set MaxVcpusPerClusterPct to 0 so we are saying to allow 0 : 1 vCPU / pCPU ratio. Now let's do some test to understand real behavior. See different behavior in screenshots belowĦ.5 U1c (build 7119157) vSphere Web Client (Flash/Flex) sets MaxVcpusPerClusterPctĦ.5 U1c (build 7119157) vSphere Client (HTML5) sets MaxVCPUsPerCore Therefore, it is good to know what you would like to achieve and double check DRS Advanced Options. However, in vSphere Client (HTML5) it sets MaxVCPUsPerCore so it is per ESXi host. If I set "CPU Over-Commitment" in vSphere Web Client (Flash/Flex) it sets MaxVcpusPerClusterPct so it is the setting per the whole vSphere Cluster. In my lab, I have VCSA 6.5 U1c (build 7119157) so I did some tests.
It is good to know how GUI setting of " CPU Over-Commitment" is mapped to DRS cluster advanced options. It is worth to mention a little bit tricky setting of these additional options via GUI.
VCPU 0 ERROR HOW TO
However, it is good to know that there are two different advanced DRS options (configuration parameters) how to specify vCPU:pCPU ratio and each setting behaves differently. It limits the number of vCPUs per pCPU in particular DRS cluster. VSphere 6.5 DRS has introduced additional option to set maximum CPU over-commitment. Some time ago I have blogged how to achieve it with PowerCLI and LogInsight - ESXi host vCPU/pCPU reporting via PowerCLI to LogInsight. Before vSphere 6.5 we have to monitor it externally by vROps or some other monitoring tool.