KVM vs Virtualbox 4.0 performance comparison on RHEL 6

Written by Gionatan Danti on . Posted in Virtualization

User Rating:  / 61

Host system consolidation results

The final target of a virtualizer is to consolidate as many guests as possible in a single host system. This capability, called consolidation rate, is a key parameter in hypervisor choice: the more it can run guests virtual machine without causing to much overhead, the better is. So, how KVM and Virtualbox fare in this discipline?

Host CPU time

As you can see, it seems that Virtualbox has a slightly lower overhead with four and eight guests, but the results with twelve guests are very close. KVM seems to cause a slightly higher I/O load also. However, keep in mind that this is only half of the truth: to depict an accurate representation, we had to consider guests performance also. The reason is clear: if a guest run slower, it will also consume lower CPU time on the host system. In the following pages we well consider guests speed also but, for the moment, lets concentrate on host load.

Consolidation rate is often limited not by CPU speed, but by main memory availability. Who is the most parsimonious between the two contenders?

Host memory usage

Well, it seems that while the 4 guests results are very similar, with 8 and 12 guests Virtualbox use more memory than KVM. This is a quite important win for KVM as, by judging from the above trend, it seems that Virtualbox's disadvantage will grow with more guests.


#1 Firmansyah 2012-06-15 10:48
This is an amazing article. Information on this article is very clear and imaginable. I currently need to decide which virtualization technology should be adopt in my company. I was previously prefer to Virtualbox, consider to both easiness and performance.
#2 Ben 2012-07-20 20:26
Thank you for this great article.
No matter how the two hypervisors perform, unfortunately they're still far away for the use in larger enviroments like terminal server farms etc. But for me, however, Virtualbox is still ahead.
#3 Erik Brakkee 2012-11-18 11:21
It would have been interesting to also see results for using raw storage instead of filesystem based storage. Raw storage can provide more performance and robustness and can also support guests running databases with mission critical data (with the correct settings). The idea is that every sync from the database to the filesystem in the guest would be directly synced to raw storage.

Raw storage is also very easy to manage on linux with logical volume management.

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