Red Hat, Novell To Package Xen 233
robyannetta writes "Watch out VMware and Microsoft. Here comes
Xen, an open-source virtualization for the Linux environment being pushed by Red Hat and Novell. Xen has also joined forces with leading Linux distributors, chip vendors and platform vendors to create a consortium that will more broadly enable open-source virtualization development and deployment." We've covered Xen before, but it's cool to see the momentum behind it growing, as more choice is a Good Thing.
What about Qemu ? (Score:3, Interesting)
I've yet to try Xen, but as of now, I just need basic windows compatibility to launch closed softwares (most of them being databases of law articles on CD-ROM to copy / paste extracts in linux Openoffice for research purpose), and Qemu does just that.
I only wish it could play GTA3-VC !
Re:Correct (Score:3, Interesting)
"Porting" (Score:5, Interesting)
But what do you have to change ? First of all, the system has to be made aware that it's not the "top top". Its physical memory is no longer contiguous (you ask Xen for memory pages, and it gives them to you in arbitrary places), it also has to be aware of absolute time that's no longer tick++. Second, you need drivers for the abstract network card and disk. Those are generally easy to write, because you just delegate the real work to Xen. VMWare is already doing something similar with its vmxnet driver for Windoze.
I'd really expect these kind of changes to the OS to be incorporated in the main linux tree, as they mature.
What do you gain from all this ? Well, SPEED. I mean, SPEED. Take a look at their research papers (wrong suggestion for the "I won't RTFA" crowd, but still ...). Their slowdowns/throughput losses (they run Postgres and Apache on a couple of virtual nodes, as opposed to a single, consolidated machine), are negligible (less than 10%). On some configurations they even got performance improvements! At the same time, VMWare and UML do considerably worse.
In general, it's very easy to "virtualize" stuff that's running mostly in user space. As soon as you have considerable OS+I/O overhead, your performance drops significantly. The para-virtualization approach (employed by Xen), pretty much gets you the best of both worlds.
Re:Uhm... (Score:4, Interesting)
Re:What's wrong with user-mode linux? (Score:3, Interesting)
Xen is already better than VMWare (Score:2, Interesting)
Xen is more similar to VM; it's already great for server farms and when things like OpenSSI become available/usable it'll mean the realization of network-wide clustering that's Tannenbaum's wet dream.
VMware/Qemu/Plex86 might be [aguably] good for those who only pretend to use their computer, but they're absolute piss for Real Work(tm).
I see a distribution paradigm (Score:5, Interesting)
Re:Uhm... (Score:3, Interesting)
Re:Uhm... (Score:2, Interesting)
So AMD (and Intel?) are planning on supporting virtualizing in their lower end CPU's in 2006?
AMD's Presidio project is suposed to [infoworld.com] be out next year, but how about intel's Vanderpool project?
I couldn't find any similar articles for Intel announcing any timeline for Vanderpool ... perhaps the Xen folks are waiting for imminent support there before committing dev resources to this?
Xen is the real deal. (Score:5, Interesting)
There are a lot of replies of the form, "Wait a minute, Xen requires that you hack up your guests! What a crock! Typical slashdot hype!" It's true that Xen is more limited than VMware's products, in that you do need to modify guests. However, this doesn't mean that Xen is a joke. (Plex86, for instance, really is a joke, because Kevin Lawton seems to pursue it only in fulfillment of an elaborate VMware-centered revenge fantasy.)
The Xen folks, on the other hand, are smart and mostly serious people. Xen, along with appropriately modified guests, solves some of the problems that our products solve, and for those areas where it fits the bill, it does so in a way that should have lasting performance advantages over full x86 virtualization. What Xen is not, in my opinion, is a virtual machine monitor, for any reasonable definition of VMM. Xen is a microkernel. They don't call it that, because it's hard to get papers about microkernels published these days, but if you think about it, the process of porting an OS to run as a guest under Xen isn't cocnceptually distinct from porting it to run as a personality under Mach or Chorus or whatever. The L4 [l4ka.org] people didn't even bother renaming their microkernel before repurposing it as a paravirtualization platform.
I think the microkernel analogy helps clarify ones thinking about the promises and limitations of so-called "paravirtualization." Hypervisors are microkernels. In the mid-90's, there was a hope that the whole world would be able to settle on the Mach microkernel. It never happened. Anybody hoping to become the only 'para-hypervisor' will face the same political and commercial challenges.
So to recap: Xen is not a replacement for VMware's products. Xen will probably not take over the world to the degree that its creators would like. Xen is not, however, a joke. The Xen researchers are mostly conscientious, smart people who, fairly enough, would like to see their work have some commercial impact. I really wish they'd stop beating their chests over benchmarks that show them beating a three year old version of our desktop product, though.