What are the differences between QEMU and VirtualBox? [closed]

Question

Recently, I found out that there is the QEMU project. I've used VirtualBox before, and I know about Xen and VMWare.

What are the differences between QEMU and VirtualBox? Should I stick with VirtualBox?
In which cases is QEMU better?

Farriery

Answer 1

Basically both have features which the other does not have, so this might ease the decision. QEMU/KVM is better integrated in Linux, has a smaller footprint and should therefore be faster.

VirtualBox is a virtualization software limited to x86 and amd64 architecture. Xen uses QEMU for the hardware assisted virtualization, but can also paravirtualize guests without hardware virtualisation. QEMU supports a wide range of hardware and can make use of the KVM when running a target architecture which is the same as the host architecture.

Xen is a Type-1 hypervisor where VirtualBox and QEMU are considered as Type-2 hypervisors (also there might be a debate considering kvm being a kernel module).

A similar question has been asked before in this community.

Endophyte

is QEMU as safe as virtualbox for sandboxing Windows? I don't want windows to have any access to my Linux OS – Hovey

@Hovey they both had security vulnerabilities allowing virtual machine escape: en.wikipedia.org/wiki/Virtual_machine_escape – Arrear

@Endophyte In the next kernel KVM will not be a kernel module anymore :) – Tush

@Tush What will it be then? I'm using 5.6.8 am I affected? – Cristobal

@Tush please state your source – Endophyte

Answer 2

QEMU with KVM is much, much faster than VirtualBox, you can test it yourself:

VirtualBox:

QEMU

Disk and CPU tests provided similar results, more or less.

Tush

That's interesting. A Web page suggest otherwise: techgenix.com/qemu-vs-virtualbox – Anopheles

@HiltonFernandes I think articles on sites like this are often primarily researched by reading other articles, so even what would be true statements can lose their original meaning after being recycled, becoming misleading. In this case I think the idea that VBox is faster comes from the fact that virtualization has an inherent speed advantage over emulation. QEMU is an emulator first and foremost, so this might hold true for VBox vs QEMU generally. But applying this broad generalization falls apart when we are talking about QEMU+KVM because QEMU+KVM is virtualization. – Mozza

Answer 3

A difference is the supported list of instructions. Virtualbox and VMware don't support the f16c-instructions supported by architectures beginning with Ivy Bridge, which limits compilations even with newer CPUs to those for Sandy Bridge and leads to other incompatibilities.

Petersham