Slashdot Mirror

That has not been true for years.
Xen 3.0 added the ability to run unmodified guests.

http://wiki.xensource.com/xenwiki/XenFaq

It also depends on having VT. Running virtualbox on a cpu old enough to not have VT support would be an exercise in frustration.

From http://wiki.xensource.com/xenwiki/XenVGAPassthrough

Xen 4.0.0 is the first version to support VGA graphics adapter passthrough to Xen HVM (fully virtualized) guests. This means you can give HVM guest full and direct control of the graphics adapter, making it possible to have high performance full 3D and video acceleration in a virtual machine.

it is, you can pass-through a GPU to a VM using Xen 4.0 or above: http://wiki.xensource.com/xenwiki/XenVGAPassthrough

Well, video drivers are userspace in Windows 7, and Xen has working PCI-E passthrough to domU. I don't think abstraction is a barrier if done properly.

http://wiki.xensource.com/xenwiki/XenPCIpassthrough
http://wiki.xensource.com/xenwiki/XenVGAPassthrough

Well, video drivers are userspace in Windows 7, and Xen has working PCI-E passthrough to domU. I don't think abstraction is a barrier if done properly.

http://wiki.xensource.com/xenwiki/XenPCIpassthrough
http://wiki.xensource.com/xenwiki/XenVGAPassthrough

Aha, at http://wiki.xensource.com/xenwiki/XenParavirtOps I find:

Features added in 2.6.36:
Xen VBD (Virtual Block Device) online dynamic resize support for resizing guest disks (xvd*) on-the-fly.

After the good advice in the comments above, if you still really really want to virtualize, you could try Xen with PCIe passthrough to DOM running your graphics intensive apps. It will appear natively to the virtualized OS. I have no experience with this - I use virtualization purely to run windows-only financial apps - but there are reports of success in the Xensource forums and examples of it working on YouTube. Good luck. See: http://lists.xensource.com/archives/html/xen-users/2009-01/msg00865.html http://www.youtube.com/watch?v=5I13E1MQbMc&feature=related

Get yourself a motherboard that support VT-d and passthrough your video card to your windows HVM for 3d perfermance in your VM. This link shows boards that have it: http://wiki.xensource.com/xenwiki/VTdHowTo

Xen has been making some progress with VGA passthrough (support was added in 4.0.0, http://wiki.xensource.com/xenwiki/XenVGAPassthrough .) Some Intel, AMD, and nVidia graphics cards are reported to work, and AMD has recenly submited patches for vga passthrough to their mailing list. I don't have any experience with it yet myself though.

P.S. I still use SCO servers running as virtual machines to run obsolete proprietary software.

Last I checked neither Xen nor KVM would run SCO UnixWare 7.1.1 :-(

http://bugzilla.xensource.com/bugzilla/show_bug.cgi?id=1391

Xen dom0 patches are available for 2.6.27, 2.6.29, 2.6.31, 2.6.32, 2.6.33 etc..most people prefer 2.6.32 atm, since that's the long-term maintained kernel from both kernel.org and xen.org. For more information: http://wiki.xensource.com/xenwiki/XenDom0Kernels . Xen developers are also busy preparing (and rewriting) the Xen dom0 support for the mainline Linux Xen pvops framework, which has been in upstream Linux since 2.6.24.

This has changed pretty much lately. A lot of new documentation has been written to the wiki, for example: http://wiki.xensource.com/xenwiki/XenCommonProblems has a lot of stuff and links to other new documentation pages. Have you heard of XCP (Xen Cloud Platform, http://www.xen.org/products/cloudxen.html)? It's a full "Xen distribution" featuring install CD, including everything needed for multi-host/pool management. No need to install custom kernels or anything. You can use OpenXenCenter (http://www.openxencenter.com/) to manage it, if you need a GUI tool.

Fedora 13 contains Xen hypervisor and tools, but it doesn't contain rpm package for a Xen dom0 capable kernel. There are unofficial Fedora rpm packages for a Xen dom0 capable kernel, based on the upstream pvops dom0 kernels (Linux 2.6.32). More information about Fedora Xen status and links to rpms see: http://fedoraproject.org/wiki/Features/XenPvopsDom0 . More information about available Xen dom0 kernel options see: http://wiki.xensource.com/xenwiki/XenDom0Kernels .

Some comments.. Xen hypervisor (xen.gz) is not meant to be integrated to Linux kernel. Xen is designed to be a separate piece of software. Xen is a secure, type-1 baremetal hypervisor, not a module for Linux. Xen dom0 ("service console") can be Linux, NetBSD or OpenSolaris. Most people use Linux as Xen dom0. When Linux is used as dom0 it needs to be able to run as Xen dom0 (obviously) - and this is where some people have had pain. For a long time the official Xen dom0 kernel patches were only available for Linux 2.6.18. This was difficult for many people and caused some distros to drop Xen dom0 kernel support because they couldn't affort porting the patches to newer kernels themselves. Today the situation is different. Xen developers are actively working on rewriting the Xen dom0 patches based on the (already existing) upstream pvops framework. pvops has been in the upstream Linux kernel since 2.6.24. Xen pvops dom0 patches are available today for the long-term maintained 2.6.32 kernel, and also for 2.6.31, 2.6.33 and 2.6.34. Novell has also forward-ported the old/traditional Xenlinux patches from 2.6.18 to first 2.6.27 and also to 2.6.31, 2.6.32 and 2.6.33. So there are many options today. For more information about the various Xen dom0 kernels see: http://wiki.xensource.com/xenwiki/XenDom0Kernels Also xen.org offers XCP (Xen Cloud Platform) which is a full platform, including installation CD and multi-host/pool management. If you use XCP you don't need to install custom kernels or anything - you get all included in the XCP bundle. More information about XCP: http://www.xen.org/products/cloudxen.html

In nutshell, Xen devs shoot in the foot here. Have they agreed to be included in main kernel three and be more welcome with patches, it would be more interesting competition here.

Why, yes, they have agreed to include their patches in the main kernel tree, but not all of them have the consent of the upstream kernel developers. The response of the Xen developers has been a significant refactoring of their code. Try reading the readily available documentation on the progress of merging Xen kernel patches upstream.

This is 2010, run your VM off a live CD!

http://wiki.xensource.com/xenwiki/LiveCD

Xen kernel developers have been busy re-writing and cleaning up the the dom0 support using the pvops framework. That work is now getting final/ready, and the Xen pvops dom0 patches will be sent to upstream Linux shortly.

About bloody time too! :)

Just looking at http://wiki.xensource.com/xenwiki/XenDom0Kernels shows what a mess Xen Dom0 is and how hard it is to get working.

The review needs to list, what the book has, that a google search will not find for free.

Off the top of my head, I'd go with coherency, structure, and a lack of insults.

Sounds just like a FAQ... which google will find for free

Google Xen FAQ first link for me was

http://wiki.xensource.com/xenwiki/XenFaq

Good coherency, although it was not, it looks like it was written in one sitting by one guy, or at least edited to look that way.

Good structure, its an outline, and the outline even looks well designed.

Lack of insults, well, its no mailing list. And for $20 or whatever the book costs, I'll glance over a mailing list post calling some dude a noob, or whatever.

You are woefully uninformed.

If you are using the (closed source, free) Citrix XenServer, the "Xenserver Guest Additions" ISO will install paravirtualised disk and network drivers, which handle IOs through a hypercall interface instead of qemu-dm's emulated devices (which, I'll grant, is hideously slow.)

If you're using GPL Xen, then the drivers at http://wiki.xensource.com/xenwiki/XenWindowsGplPv (that page points at source code, there are MSIs floating around, ask your distributor) accomplish the same ends. I've used them in the handful of cases I've needed to virtualise Windows at home. They're on par throughput-wise with the Citrix stuff I use at work.

Either way, such an approach gives IO performance on par with ESX, and the ability to mix and match this sort of VM with paravirtual Linux and Opensolaris guests on the same cluster of hosts buys you a shit ton in flexibility (IO performance in paravirtual guests exceeds anything that fully virtualised Xen or ESX will ever achieve, period, end of story.)

Yes, Citrix, also the guys that support the open source Xen virtualization platform.

Yes, it does: http://lists.xensource.com/archives/html/xen-devel/2008-06/msg00430.html

We have recently adopted a phased approach of deploying new thin clients as our estate of traditional desktops hit retirement. After having seen several false dawns and uncomfortably proprietary solutions in the last 15 years, it was only now that we have been happy enough with the whole solution (thin client HW, network connectivity, back-end virtualization SW) to take the plunge.

There are now a range of HW clients (we use ChipPC).
There are a couple of viable virtualization systems (we use Citrix Xen, without the presentation server "tax").
We've chosen a dedicated virtualization hardware appliance on the back-end from 360is.

Nice FUD.

No, this is not what happened at all. Simon Crosby (biggest blowhard ever), shot his mouth off proclaiming that VMware are a bunch of idiots, but he can't show it cause of the EULA. Well, unbeknownst to all his readers Xen had submitted their paper to VMware for approval, which they did approve and Xen published. It showed that Xen was competitive in most of the benchmarks, but fell short in a number and beat ESX in only 1, SPECjbb on Linux.

Good luck finding anything from this whole exchange, Citrix purged there blogs of the entire ordeal. Here is the paper WITH the data, no redactions. I am not seeing this "everywhere else Xen killed", could you point it out to me?

As a side note VMware is very liberal with their benchmark policy. As long as you actually benchmark in a sane manner they will let you publish no matter the result.

I do think that another host using an automated provisioning system that is compatable with EC2 would be a good thing- If I wasn't absolutely swamped by my dayjob, I'd try to implement such a thing.

SuSe posted their patches to the Xen-devel list mid-feb. If other distros want to take their patches, they would be able to run paravirtualized in Windows. The patches met with some resistance from the Xen developers - so if they get into upstream development remains to be seen..

As ridiculous as it may sound, it's theoretically possible for a Windows driver to be licensed under the GPL.

It's theoretically possible, but in practice such a driver would have to avoid any use of the Windows DDK (including any header files). The Windows DDK is licensed in such a way to actively prevent GPL'd drivers, though other licenses that MS can steal from like BSD are OK.

Rich.

I know this article is old, but can we agree to this?

First, a couple of background questions... Andy, you believe wholeheartedly in microkernels, right? Do you believe in them more than Minix, or is this merely a shameless plug for your product, Minix?

Based on those two responses, here is my proposal.... Assuming you believe in microkernels more than Minix, why not take a leadership role in GNU/Hurd and get that project going, again? http://www.gnu.org/software/hurd/hurd.html

Perhaps, you can get assistance from the Xen people, too. http://www.xensource.com/

That's my modest proposal....

(But will it run Linux?) It will run Linux -- one of the data sheets implies that Linux only runs in 32-bit mode, while Windows can run 64-bit. Perhaps there's more documentation that provides more details."

How free is it? I don't know; I haven't read the licenses, so I don't know if it's free-beer-only-closed-source or Fully Stallman Compliant (unlikely) or somewhere in between (probably.)

"XenSource has been in the news twice this week -- Monday they release a product, then Tuesday they get bought for $500m by Citrix. Here's Network World's take on the buyout and on the product. It looks like the product is packaging new releases of several of their components -- there's a 64-bit hypervisor version 3.1 that uses the Intel and AMD hardware tricks, APIs, management tools, and XenMotion, which lets you move running virtual machines around. According to Xen's product page, the free-beer XenExpress version gets the hypervisor, APIs, and some of the management tools, but not the fancier management or XenMotion, and it's somewhat crippled in terms of capacity (max 4 VMs, 2 CPUs, 4GB RAM, while the commercial versions support 128GB total RAM, larger VMs, and unlimited VMs and CPUs.)

(But will it run Linux?) It will run Linux -- one of the data sheets implies that Linux only runs in 32-bit mode, while Windows can run 64-bit. Perhaps there's more documentation that provides more details."

http://www.networkworld.com/news/2007/081507-citri x-xensource-desktop-server-virtualization.html?nlh tspec=081507specialalert1&

"XenSource has been in the news twice this week -- Monday they release a product, then Tuesday they get bought for $500m by Citrix. Here's Network World's take on the buyout and on the product. It looks like the product is packaging new releases of several of their components -- there's a 64-bit hypervisor version 3.1 that uses the Intel and AMD hardware tricks, APIs, management tools, and XenMotion, which lets you move running virtual machines around. According to Xen's product page, the free-beer XenExpress version gets the hypervisor, APIs, and some of the management tools, but not the fancier management or XenMotion, and it's somewhat crippled in terms of capacity (max 4 VMs, 2 CPUs, 4GB RAM, while the commercial versions support 128GB total RAM, larger VMs, and unlimited VMs and CPUs.)

(But will it run Linux?) It will run Linux -- one of the data sheets implies that Linux only runs in 32-bit mode, while Windows can run 64-bit. Perhaps there's more documentation that provides more details."

http://www.networkworld.com/news/2007/081507-citri x-xensource-desktop-server-virtualization.html?nlh tspec=081507specialalert1&

Get real. All any vendor needs to do to use the includes xen ingredient brand is listed here on the xensource site. http://www.xensource.com/company/legal.html#f Seems pretty darn clear. the Hat doesn't want to give credit to anyone but the Hat. Imagine that. Nice try-really cheap FUD. everybody wants a free lunch.

Most people are unaware of the work going on as part of Xen for support of Trusted Computing. The Security Enhancements for Xen project is working on integrating the TPM into Xen so that virtual machines will get "measured" (hashed into the TPM) and Xen can report which VM is running using Remote Attestation. This way if someone hacks their VM, remote parties will know about it. Other technologies related to this include Intel's Trusted Execution Technology (aka LaGrande Technology) which adds security beyond the TPM to really lock down the machine. See this mailing list thread for discussion of the recent patch adding TXT support to Xen.

Personally I think this is fine and can really increase the security and utility of virtualization. But particularly with the recent release of GPLv3 and controversy over trusted computing it is interesting to see Xen moving in this direction. I imagine that it means that Xen will stick to GPLv2.

Most people are unaware of the work going on as part of Xen for support of Trusted Computing. The Security Enhancements for Xen project is working on integrating the TPM into Xen so that virtual machines will get "measured" (hashed into the TPM) and Xen can report which VM is running using Remote Attestation. This way if someone hacks their VM, remote parties will know about it. Other technologies related to this include Intel's Trusted Execution Technology (aka LaGrande Technology) which adds security beyond the TPM to really lock down the machine. See this mailing list thread for discussion of the recent patch adding TXT support to Xen.

Personally I think this is fine and can really increase the security and utility of virtualization. But particularly with the recent release of GPLv3 and controversy over trusted computing it is interesting to see Xen moving in this direction. I imagine that it means that Xen will stick to GPLv2.

"Logging into servers at my company and often seeing 5% CPU usage doesn't exactly fill me with pride either"

Ever heard of server virtualization ? http://www.vmware.com/ or http://www.xensource.com/

I've cut our datacenter footprint by over 35% using virtual servers.

You can read the slides and if try contacting the author if you're interested.

My experience with Xen has been sketchy too; I stopped using it after 3.0.2. VMs that don't die, failed VM state saves, failed migrations, the list goes on.

OK, maybe I didn't buy the commercial version, but it's a bit discouraging when the free download page http://xensource.com/download/index_oss.html has the text:

"The downloads on this page have been built from the latest Xen 3.1 official release. They have undergone limited testing, are not supported in any way whatsoever, and will be fixed on a best-effort basis only."

Even if I *was* using the commercial version, this doesn't inspire much confidence.

ESX pricing is in the multiple-thousands of dollars per machine. Which, if you're putting together a collection of $20k-$30k machines probably isn't that bad.

But it's horribly overpriced for the smaller market. Picture a small company with 4-12 servers in the $3k-$5k range and a $10k SAN unit. They'd like to be able to pool their servers so that if one box goes down due to hardware failure, services continue to be available.

VMWare's pricing makes that a non-starter.

Xen Enterprise pricing is a lot more reasonable for a small/medium business. VMWare only seems interested in the "big iron" shops who have budgets of $500k+ per year to spend on software licenses.

Hell, in a small business, you don't even care if there's a few minutes of downtime. At least, ss long as you can get things back up and running quickly on one of the less-utilized servers.

Another great reference that I ran across after posting here. This is really what I was looking for. Posting anon to not be karma whore.

VMGL [PDF warning]

If your distro of choice doesn't package Xen nicely for you, and you're not patient enough to roll your own Xen from the source, here's what you need: Xen Express. This is the easy-to-use version you're looking for.

HP is a partner to both companies, you just didn't look properly. Although HP is just a System Management[Xensource.com] partner.

Let's look at what are the companies in partnership with XEN and with SWSoft (OpenVX copyright owner). HP appears only on one list.

http://www.xensource.com/partners/

http://www.swsoft.com/en/partners

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. Paravirtualization needs modified guests, but the outcome is so good that VMware is trying paravirtualization too.

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.

Besides, by what Wikipedia says about OpenVZ, it seems to be more a solution like jails, 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.

Performance:

Iam not sure why people think xen is so much faster than ESX. Xensource themselves claim "xensource performance as well as vmware" in thier white paper which shows VMware to be slower only in specjbb on linux (paravirt vs bt which is unfair comparision). In fact paravirt should be compared to the VMI.

http://blogs.xensource.com/rogerk/wp-content/uploa ds/2007/03/hypervisor_performance_comparison_1_0_5 _with_esx-data.pdf

BTW VMware does allow benchmarking as its aparent from the paper xensource put out.

unless it is graphically intensive (dx9, requiring 3d acceleration) everything can either be emulated (wine) or virtualized (xen or vmware). unfortunatally there is no such thing as a free lunch - there is the additional cost of maintaining the extra layer, and ever for highly optimized applications there is still a performance hit (5% or so)

Yeah, they posted a complete version recently:

http://blogs.xensource.com/rogerk/wp-content/uploa ds/2007/03/hypervisor_performance_comparison_1_0_5 _with_esx-data.pdf

Although the focus is on virtualization and its effect on performance, I noticed that the author disclosed that he ran the tests on VMWare. The VMWare EULA states in section 3.3 "You may use the Software to conduct internal performance testing and benchmarking studies, the results of which you (and not unauthorized third parties) may publish or publicly disseminate; provided that VMware has reviewed and approved of the methodology, assumptions and other parameters of the study.".

This relates to the earlier slashdot story where xensource had to redact areas of their performance whitepaper

I wonder if they gave him the green light to report these results on VMWare?

Although the focus is on virtualization and its effect on performance, I noticed that the author disclosed that he ran the tests on VMWare. The VMWare EULA states in section 3.3 "You may use the Software to conduct internal performance testing and benchmarking studies, the results of which you (and not unauthorized third parties) may publish or publicly disseminate; provided that VMware has reviewed and approved of the methodology, assumptions and other parameters of the study.".

This relates to the earlier slashdot story where xensource had to redact areas of their performance whitepaper

I wonder if they gave him the green light to report these results on VMWare?

http://www.xensource.com/xen/

The last time I checked VMware Virtual Infrastructure 3 had a number of features not found on the Microsoft product such as live migration of virtual machines. I also prefer the VMware management tools. To take advantage of the full VI3 features you should have two or more servers connected to a SAN. This is not inexpensive, but the payoff will be better uptime. Think of it as RAID for servers. Of course you don't need the SAN, but you lose the live migration features. The advantage of VI3 over the free VMware Server is the better performance and management features.

I prefer the VMware tools. They are more mature then Microsoft's. The MS tools will catch up I am sure, but VMware has a couple years head start. VMware also runs Linux better then Microsoft's product.

Because the VMware images are portable across all of the VMware tools, you can develop a server image on your workstation and deploy it onto the production VI3 machines. VMware has a great snapshotting feature. It is great when testing and deploying patches. You take a snapshot of the virtual machine. Boot it in a network isolation mode. Install and test the patch. If it works you either install the patch on the production vm, or just swap the snapshot for the live system. If you time it right there is no downtime.

You may also want to consider XenSource. It is a commercial product based on the open source Xen. The advantages of the commercial product are the management tools and support. Xen is blazing fast.