virtualbox.org

Hi everyone,

I'm trying to use Virtual Box on a huge server (40 core and 512GB RAM).

This server run under Windows 2008 R2, and I can't remove the OS (there are lot of other stuff on the machine).

I created a Virtual Machine under Cent OS which I set the memory to 450000MB.

When I run my process on the VM, it become very slow to use, if I execute "top" through the command line. It indicate that the VM have got 454252804KB as memory. But when I display the windows task manager of the host, the amount of memory used by Virtual Box is about 2GB.

- I checked the Bios and the VT and Virtualisation options are enable.
- I uninstalled Hyper-V.
- I tried with 32GB memory and I've got the same result
- I checked if I've got the 32 bit version of virtual box, but, I've definitely got 64bits version
- I rebooted my server

It change nothing, have you got any idea to help me using the hardware resources of my server through Virtual Box?

You don't say exactly what the host is. If the host OS is 32bit then it can't allocate more than 2GB RAM for any app, including VirtualBox.

If you have a 64bit host and guest OS then make sure you choose a 64bit guest OS template.

Also your terminology is rather confusing: you say "this server run under Windows 2008", plus you say "I created a Virtual Machine under Cent OS"... if you are saying that you created a nested VM then we don't support that, and that would certainly limit you to 32bit guests-within-guests.

If you mean that you have a W2K8-64bit host and want to run a CentOS 64bit guest, but can't, then see FAQ: I have a 64bit host but can't install 64bit guests.

Thanks to take time to answer me, my english is not perfect. But, you guess what my mistake is.

I'll check point 3 of the FAQ tomorow.

There's no need to apologise for your English, my only concern is to be sure I answer the correct question!

I've got a lot of process that are running on the host. Do you know if there is an easy way to check if one is using VT-x.

No, there is no way to easily identify the host process (if any). The best way is simply to be aware of what software is installed on the host, and the resources it is likely to need. In case of doubt you can sometimes prevent your shortlist of suspects from loading at boot time, confirm that this eliminates the problem, and then reintroduce them one at a time until the problem comes back.

If you post a VM log file (for any VM) then we can eliminate a number of possibilities right away.

Ok, here it is the log (attached to this message), if it help you to better understand the issue.

I deleted duplicate lines and replaced by "..." in order to fit the 128KB limitation upload file size of this forum.

Also, I found that Virtual Box allocate memory outside of the host process "Virtualbox.exe". When I shutdown the VM physical memory on the system go down. But, that doesn't explain why the VM access is so slow.

Wow. I've never dreamed of a VM with 250GB virtual RAM and 32 cores assigned. And the host can easily afford it too.

Your issue is not that VT-x is in use by something else. According to this log, VT-x is available and is successfully enabled. There are also no memory allocation errors. Even if you accidentally installed a 32bit guest OS that should not change the allocation.

I would tend to doubt whatever tool you are using to determine that the VM is only using 2GB RAM. That might be possible if you enabled memory ballooning, but it looks like you have not.

As I write previously, I checked the Physical Memory occupied by all the host OS (Windows 2008 Server R2) at different step of my guest :
- when the VM is ON
- and then when the VM switch ON to OFF

And, I note that the total amount of memory decrease of a huge number of gigabyte (around 40GB) when the guest is switched OFF. So, I think that Virtual Box is not using normal OS allocation but it use special stuff to reserve memory. So we can't measure easily the memory occupied by the Virtual Box process.