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KVM or VirtualBox

asked 2011-11-15 00:50:03 -0500

Mohan G gravatar image

updated 2011-11-15 01:08:57 -0500

mether gravatar image

Hi, I read that virtualization is faster with QEMU/KVM. But my intel-laptop does not satisfy the KVM hardware requirements. It has a 32-bit processor and no VMX flag.

So, in this case should I go with Oracle VirtualBox or do I have any chance with KVM? I mean, will KVM run on my laptop (may be at a lower speed, atleast equal to VirtualBox) or will it not function at all ?


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answered 2011-11-15 01:16:07 -0500

mether gravatar image

First make sure that your system does not support it. Most recent hardware does but you will have to enable support in BIOS explicitly as it is not turned on by default typically.

KVM is a kernel module that needs support in the CPU for virtualization extensions and uses Qemu in the user space. Without that support, Qemu can still run but it will very much slower. If your hardware doesn't have the support, then VirtualBox may be the better solution and will be faster than Qemu.

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answered 2011-11-15 05:32:39 -0500

hhlp gravatar image

what is KVM

KVM (for Kernel-based Virtual Machine) is a full virtualization solution for Linux on x86 hardware containing virtualization extensions (Intel VT or AMD-V).

Using KVM, one can run multiple virtual machines running unmodified Linux or Windows images. Each virtual machine has private virtualized hardware: a network card, disk, graphics adapter, etc.

The kernel component of KVM is included in mainline Linux, as of 2.6.20.

KVM as the back-end virtualization for non-graphic servers and libvirt as its toolkit/API. Libvirt front ends for managing VMs include virt-manager (GUI).

Check that your CPU supports hardware virtualization

To run KVM, you need a processor that supports hardware virtualization. Intel and AMD both have developed extensions for their processors, deemed respectively Intel VT-x (code name Vanderpool) and AMD-V (code name Pacifica). To see if your processor supports one of these, you can review the output from this command:

egrep -c '(vmx|svm)' /proc/cpuinfo

 If 0 it means that your CPU doesn't support hardware virtualization.

 If 1 (or more) it does - but you still need to make sure that virtualization
 is enabled in the BIOS.


can run a "guest" operating system in a window of the host operating system without giving it direct access to your computer's hardware. (Instead, Virtualbox passes hardware-related instructions through the "host" operating system's drivers.) VirtualBox can run all versions of Windows, Linux, and many other x86- and AMD/Intel-based 32- and 64-bit operating systems as either a host OS or as a guest OS. Although some versions of Linux exist that are optimized to run as a guest OS in a virtual environment, any Linux operating system usually will function equally well.

Some typical reasons to use a Virtual Machine include providing a self-contained environment in which to experiment with new software without risking damaging changes to the host operating system to run legacy operating systems and software that may no longer be supported by newer operating systems

No special hardware is required to run a virtual machine, although recent processors have virtualization "hooks" which interact specifically with virtual machines to improve performance.

there are 2 virtualbox :

VirtualBox : Oracle VM VirtualBox
VirtualBox-OSE : A general-purpose full virtualizer for PC hardware

the principal difference is OSE is open source and doesn't have VRDP and usb support.

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I also think, this should have been the best answer! May be Mohan was looking for a simple answer & got confused with the detailed description from hhlp!

anishjp gravatar imageanishjp ( 2013-12-10 01:58:25 -0500 )edit

answered 2011-11-15 20:42:05 -0500

E. Lewis gravatar image

I have no experience with QEMU/KVM. I have used VirtualBox for several years (since version 1.6) with excellent results on a variety of machines. It has been very reliable and fast running MS 'Windows XP' guest under both Ubuntu and Fedora hosts. My experience has also shown MS 'Windows XP' to me more reliable under VirtualBox than it was under native boot. We also run MS 'Windows 7' under VirtualBox with excellent results.

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answered 2013-12-05 14:43:55 -0500

williamjmorenor gravatar image

If your CPU not suport KVM you can try with VMWare like a option to Virtual Box. There is a free edition of VMWare so you can try if have a better perfomance than Virtual Box

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Asked: 2011-11-15 00:50:03 -0500

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Last updated: Dec 05 '13