Performance Evaluation of Xen Vs. OpenVZ 116
An anonymous reader writes "Compared to an operating-system-level virtualization technology like OpenVZ, Xen — a hypervisor-level virtualization technology that allows multiple operating systems to be run with and without para-virtualization — trades off performance for much better isolation and security. OpenVZ's performance advantage due to running virtual containers in a single operating system kernel can be significant. A performance evaluation study (PDF) done by researchers at the University of Michigan and HP labs provides insight into how big a performance penalty Zen pays and what causes the overheads (primarily L2 cache misses)." From the report: "We compare both technologies with a base system in terms of application performance, resource consumption, scalability, low-level system metrics like cache misses and virtualization-specific metrics like Domain-0 consumption in Xen. Our experiments indicate that the average response time can increase by over 400% in Xen and only a modest 100% in OpenVZ as the number of application instances grows from one to four... A similar trend is observed in CPU consumptions of virtual containers."
And OpenVZ works with FreeBSD? Windows? (Score:1, Interesting)
Does anyone have links to show the support?
Re:And... (Score:3, Interesting)
How should someone who is satisfied witn VMWare decide whether an alternative would be an improvement? When the license terms for VMWare prohibit any benchmarking its kind of hard to make a decision.
Appples and oranges... (Score:4, Interesting)
Xen, is like VmWare or Qemu and provides an independent virtual machine for each system. These systems can be anything at all: Windows, Linux, BSD, whatever.
Performance wise, OpenVZ is bound to win, because it is a different solution to a different problem.
Re:Stop the press (Score:3, Interesting)
Hypervisor for both (Score:2, Interesting)
Re:And... (Score:1, Interesting)
http://blogs.xensource.com/rogerk/wp-content/uplo
Xensource themselves claim "xensource performance as well as vmware" in thier white paper which shows VMware to be slower only in specjbb and xensource is slower in some areas. And this is the highly optimized commercial version (not free, thousand something per core - still cheaper than vmware though)
Re:Stop the press (Score:5, Interesting)
Yeah but Xen is still a royal PITA to get running. KVM wasn't bad, and VMWare was pretty easy. I haven't even seen OpenVZ.
Yes, Xen is harder to install. But to compare it with KVM ... did you try to use them? KVM (at least, last time I tried -- which was only a couple weeks ago) is still in development, and the performance is so low compared to Xen that it's not even funny.
On the other hand, VMware is very nice, specially the free Server edition, and it's really easy to use. But even so, performance is better in Xen. Check this [xensource.com]. Paravirtualization needs modified guests, but the outcome is so good that VMware is trying paravirtualization too [vmware.com].
VMWare is so far ahead it will take some time for Xen to be considered out of the hobbyist market and in the commercial one
What do you think is needed for Xen to be considered apt for commercial use? Remember that Xen can use unmodified guests if the hardware supports VTX/SVM instructions, which means that it can run Windows. Pretty front-ends? Xensource (which is slashdotted now, I guess, because it times out from here) offers one, and you also have Enomalism [enomalism.com].
Besides, by what Wikipedia says about OpenVZ [wikipedia.org], it seems to be more a solution like jails [wikipedia.org], because it uses the same kernel for both the host and the guest systems. The phrase "glorified chroot" comes to mind, though I'm aware that it's more than that (just adding it for the sake of trolling, I guess :-)). Xen, VMware and QEMU/KVM are, on the other hand, real virtualization solutions, where all the virtual system runs completely isolated.
I wouldn't recommend Xen for home use (VMware Server is a better and easier option, IMHO), but saying that it's not ready and comparing it to QEMU/KVM is almost a joke.Much better isolation and security? Hmm... (Score:3, Interesting)
I guess I have to correct you here. Xen trades off performance for an ability to run different kernels, and this has nothing to do with either isolation or security. So, Xen is good when you want to run different kernels (different OSs).
OpenVZ, on the other hand, employs a single kernel model, which makes it suitable for you if you only want to run Linux (different distros are possible, different kernels are not). But in this very field OpenVZ is way better than Xen -- not only in terms of performance, but also scalability, manageability, density, and usability.
Speaking of isolation and security, OpenVZ runs on thousands of ISP/HSP servers, and everyone can buy a VE (Virtual Environment) for about 10-15 bucks a month. There one have a root account and can try to exploit the system in all the possible ways. So far those HSPs are not out of business yet, that practically proves the system is secure and properly isolated. More to say, security comes from the constant care, and we (OpenVZ team) do care for security a lot, see this blog entry [openvz.org] for some more details.