VB 6.1.14 CentOS8 can't assign more than 1 cpu

[rpyne]

I'm running VirtualBox 6.1.14 on CentOS8 host and guest on a machine with 128 G RAM and 24 CPU cores. I only have one VM running and want tp assign it 4 CPUs. I tried to assgn 4 CPUs when I created the VM and I've tried both the phpVirtualBox interfave and VBoxManage modifyvm to change it. So far, I cannot get more than 1 CPU assigned.

TIA for any help.

[scottgus1]

See I have a 64bit host, but can't install 64bit guests post #1. Ignore the stuff about Hyper-V, that's for Windows PCs.

[rpyne]

See I have a 64bit host, but can't install 64bit guests post #1. Ignore the stuff about Hyper-V, that's for Windows PCs.

The exact machine is a Dell PowerEdge R815 with dual AMD Opteron 6168 processors. Everything I can find says they do have AMD-v.

I have two of these machines, the other one has dual 6128 (8 core) processors and I have several Vbox VMs running on it with multiple CPUs. It is running VirtualBox 5.0.40 on CentOS 7.4.

[scottgus1]

The only thing that we could use to help is a VM's vbox.log. If AMD-V is enabled it will have a line "AMD-v with nested paging" or "AMD-v with unrestricted execution" or something like that. If the BIOS switch for AMD-v is off then the CPU's AMD-v won't get used. We can't help with how to turn it on in the BIOS.

[rpyne]

I did find these lines:

00:00:00.172151 HM: HMR3Init: AMD-V w/ nested paging
00:00:00.465514 HM: Using AMD-V implementation 2.0
00:00:00.465520 HM: AMD-V revision = 0x1
00:00:00.465521 HM: AMD-V max ASID = 64
00:00:00.465523 HM: AMD-V features = 0x40f
00:00:00.465567 HM: VT-x/AMD-V init method: Global

[scottgus1]

I don't see anything strange in the log. Your host PC seems well-provisioned.

What happens when you try to set more than one CPU? If you get an error, please post the exact error message.

[rpyne]

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.

[scottgus1]

What about doing it in the main Virtualbox window's Guest Settings? Check for any error messages there.

[fth0]

Just in case, note that you can only change the number of vCPUs while the VM is not running. (@scottgus1: The VBox.log file is from a VM started before this thread and still running.)

[rpyne]

What about doing it in the main Virtualbox window's Guest Settings? Check for any error messages there.

This is a headless machine with no windowing system installed.

[rpyne]

Just in case, note that you can only change the number of vCPUs while the VM is not running. (@scottgus1: The VBox.log file is from a VM started before this thread and still running.)

I have tried both, with the VM posered off and with it running (CLI only).

The log was from the VM after I had tried several things and started this thread, and have since shut it down, tried setting the number of CPUs and restarted it at least three times.

[rpyne]

I also rebooted the host machine.

Here is the log from the most recent boot.

[scottgus1]

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.

[scottgus1]

and with it running

This should have given you an error message: "The machine 'vm name' is already locked for a session (or being unlocked)"

[rpyne]

and with it running

This should have given you an error message: "The machine 'vm name' is already locked for a session (or being unlocked)"

No error message.