virtualbox.org

Strange. Mine forms that error when I try the vboxmanage modfyvm --cpus command on a running VM.

Let's see what a working multi-processor guest copied over and registered on your host does.

scottgus1 wrote:Can you make a guest with multiple processors on a different PC than copy the guest folder over to this host and run it? It will test if your existing host is having trouble with the multiple processors.

The only place I have that I can do that is running VirtualBox 5.0.40 if that will work.

Should work OK, VMs ought to be runnable as Virtualbox upgrades.

rpyne wrote:Here is the log from the most recent boot.

This is again a VBox.log file from a VM that has only 1 CPU configured. Can you also provide the idaho.vbox file? If that file also shows that only 1 CPU is configured, we may have to concentrate on the VBoxManage command you've been using.

rpyne wrote:I've tried both setting the number of CPUs through the phpVirtualBox interface, and with VBoxManage modifyvm "idaho" --cpus 4

Neither give any error message, nor do they change the number of CPUs assigned.

What exactly do you mean by "nor do they change the number of CPUs assigned"? I'm getting the impression that perhaps we have some misunderstanding here ...

fth0 wrote:

rpyne wrote:Here is the log from the most recent boot.

This is again a VBox.log file from a VM that has only 1 CPU configured. Can you also provide the idaho.vbox file? If that file also shows that only 1 CPU is configured, we may have to concentrate on the VBoxManage command you've been using.

rpyne wrote:I've tried both setting the number of CPUs through the phpVirtualBox interface, and with VBoxManage modifyvm "idaho" --cpus 4

Neither give any error message, nor do they change the number of CPUs assigned.

What exactly do you mean by "nor do they change the number of CPUs assigned"? I'm getting the impression that perhaps we have some misunderstanding here ...

Even though I tried to change the number of CPUs assigned to the VM, it still would only use 1 CPU.

Thank you to all that responded and helped. I found the problem(s).

On the Guest Extended Features settings, I needed to enable both PAE/NX and Nested VT-x/AMD-V

And I am embarrassed to admit that the reason I was getting no error message from VBoxManage modifyvm "idaho" --cpus=4 is that I was executing it as root instead of the vbox user.

Again, thank you for the help. It was instrumental in guiding me to find the problem(s).

Thanks for reporting back!

Using VBoxManage as the wrong user was obviously the problem, but I doubt that the other settings played a role: AFAIK, the PAE/NX setting is ignored for 64-bit guests (it's handled as implicitly active), and most people provide 2 vCPUs to their VMs without ever enabling Nested VT-x/AMD-V, which may create an unnecessary performance overhead. Can you change them back and test if they are really needed in your case?