Desperately Seeking Xen 192
AlexGr sends us to an excellent article on the state of Xen by Jeff Gould (Peerstone Research). He concludes that the virtualization technology has some maturing to do and will face increasing competition for the privilege of taking on VMWare. Quoting: "What's going on with Xen, the open source hypervisor that was supposed to give VMware a run for its money? I can't remember how many IT trade press articles, blog posts and vendor white papers I've read about Xen in the last few years... The vast majority of those articles — including a few I've written myself — take it as an article of faith that Xen's paravirtualizing technical approach and open source business model are inherently superior to the closed source alternatives from VMware or Microsoft."
VirtualBox performance (Score:3, Interesting)
Because.... (Score:3, Interesting)
Host OS the one with better drivers (Score:3, Interesting)
If I have to maintain two separate OS's, I'd rather have the outermost OS (host OS) be the one that has the best drivers, the most hardware support. Also, since very few virtualization solutions work with 3D gaming (and even the one that does, it still has large overheads I think), you want your host OS to be the one that has all the games. So, for my purposes anyway, I need Windows as the host OS, and Linux as the guest OS. Xen doesn't run under Windows, only Linux. So that leaves me with either commercial virtualization software, or a few open source projects that haven't matured yet (eg. coLinux).
(granted, having Windows on the outside makes your machine much less secure than the other way around, but personally, I'm more interested in having all my peripherals work the day they're released, and having all my games available)
Using it... (Score:5, Interesting)
You can choose to believe the hype or not, as you wish, but I'm using Xen in my production environment, and it's simply fantastic. I've got friends with companies who are doing it as well, and it really changes how you think about administration.
Of course, there are some learning curves. For example, how you manage 3-7 servers is completely different from how you manage 20-30, even if they are all virtual. There's a lot more emphasis on system images, isolating functionality, reproducing configurations. On the other hand, dev environments are so much easier to build-up and tear down.
I just wish the OpenBSD port was in a usable state. The mercurial servers hosting it are often down, and even when they're up, I haven't been able to get a working kernel compiled from the sources (even after doing some of my own bugfixes). And last I saw on the Xen lists, Christoph Egger (the guy doing the OpenBSD port) submitted a security patch related to stack slamming, and the Xen guys were kind of like, "meh, security's not really a priority..."... Oh well, here's to keeping my fingers crossed
Re:6ms??? (Score:2, Interesting)
YMMV, depending on usage during the time of the switch, but Xen starts migrations by copying over memory *while the original VM is running*. Then, the original VM is suspended, checked one last time for data consistancy (the delay), then the VM is brought back up by the new host.
[PDF warning] Live Migration of Virtual Machines [google.com]Re:Currently using Xen... (Score:3, Interesting)
ping...64 bytes from xxxx...5 ms
ping...64 bytes from xxxx...5 ms
ping...64 bytes from xxxx...11 ms
ping...64 bytes from xxxx...5 ms
ping...64 bytes from xxxx...5 ms
The bump to 11ms was the transition between real machines.
We use it because we like to have lots of machines doing different things at different times. The developers have wild ideas, so we give them what they want as far as an OS, and create and destroy as necessary. We keep the migration as an option in case of failure; we don't do it on a regular basis.
Re:Fundamental performance issues (Score:4, Interesting)
For CPU we used SPEC CPU 2006 and score about 5-6ish % on VMWare as the same test done on those blades in hard metal. Xen is undiscernably different to the subjective eye than hard metal. I would have to break out large batch testing methodology and run the results through inferential statistics to conclude that there was a difference at all.
I/O is a different story.
The Xen performance claims and the VZ performance claims aren't really useful. They're theoretical. As in, "theoretically, we can stack 100 operating systems on this blade efficiently." Think about that. That's just plain nuts. I can't think of a real use case for that.
BTW, if you like OpenVZ, and have the right use case, the commercial Virtuozzo product ranks as the "best virtualization technology that no one has ever heard of" in my book. They really have their IT management story down pat.
C//