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171 comments

KVM vs XEN (0)

nereid666 (533498) | more than 2 years ago | (#36328812)

Another episode of the KVM vs XEN battle!!

Re:KVM vs XEN (1)

GPLHost-Thomas (1330431) | more than 2 years ago | (#36328882)

Oh, I meant to write it is NOW included, sorry for the typo, maybe someone can change it???

Re:KVM vs XEN (1)

Anonymous Coward | more than 2 years ago | (#36328900)

An editor could probably fix that, but since all we have is hashish-addled dupemonkeys, it's stuck that way.

Re:KVM vs XEN (2)

GPLHost-Thomas (1330431) | more than 2 years ago | (#36328996)

Well, the issue is that I couldn't see the submit buttons at the bottom when doing my submission. They were display too much at the bottom of the screen, and I could see only the few top pixels of them. I wanted to click on "Continue editing", but unlucky for me, it was posted without giving me a chance to rectify. So I don't think it's really my fault here... Maybe someone at /. wants to test the submission display so that it's better on Firef ^W Iceweasel 4.0.1 (my own backport running on Squeeze)...

Re:KVM vs XEN (0)

Anonymous Coward | more than 2 years ago | (#36329518)

maybe someone at /. wants to test the submission display system so that its better on... ANYTHING :(

Re:KVM vs XEN (1)

catmistake (814204) | more than 2 years ago | (#36328966)

Just what the hell is the difference between a bare iron hypervisor and KVM? Aren't they pretty much the same? Where are the patent lawsuits?

Re:KVM vs XEN (4, Informative)

pasikarkkainen (925729) | more than 2 years ago | (#36329014)

Xen has features that KVM doesn't have (by design). For example Xen "stubdomains" and "driver domains", full memory address space separation between domains, etc.. and of course it's good to have multiple opensource virtualization platforms, competition is a good thing!

Re:KVM vs XEN (1)

catmistake (814204) | more than 2 years ago | (#36329072)

thanks, but it still sounds to me like the difference between, say, Linux and BSD and SysV... yeah, different... but, oh so similar (basically they're all kernel+user land). So sounds like Xen is a little more sophisticated. But besides that, besides features, at their core, what really is all that different between KVM and bare iron hypervisors?

Re:KVM vs XEN (3, Informative)

pasikarkkainen (925729) | more than 2 years ago | (#36329106)

Actually the design is pretty different. Take a look at these slides: http://www.slideshare.net/xen_com_mgr/why-xen-slides [slideshare.net] . That should explain the differences. Xen is also multi-OS, ie. you can use also BSD/Solaris in addition to Linux as a Xen host, while KVM is Linux-only as host.

Re:KVM vs XEN (1)

catmistake (814204) | more than 2 years ago | (#36329186)

Thanks again. From your link:: "KVM has a very different model - Linux kernel as hypervisor"
Aha! KVM is a hypervisor too? Xen has no kernel? Again... besides the features... the function appears the same to me. Take KVM, remove the drivers, make it tiny, minimalistic... and besides features, the model appears the same to me. Xen is more advanced, more features... but basically, they're both bare iron hypervisors, right?

Re:KVM vs XEN (5, Informative)

pasikarkkainen (925729) | more than 2 years ago | (#36329284)

Xen is a secure baremetal hypervisor (xen.gz), around 2 MB in size, and it's the first thing that boots on your computer from GRUB. After Xen hypervisor has started it boots the "management console" VM, called "Xen dom0", which is most often Linux, but it could also be BSD or Solaris. Upstream Linux kernel v3.0 can run as Xen dom0 without additional patches. Xen dom0 has some special privileges, like direct access to hardware, so you can run device drivers in dom0 (=use native Linux kernel device drivers for disk/net etc), and dom0 then provides virtual networks and virtual disks for other VMs through Xen hypervisor. Xen also has the concept of "driver domains", where you can dedicate a piece of hardware to some VM (with Xen PCI passthru), and run the driver for the hardware in the VM, instead of dom0, adding further separation and security to the system. Xen "Driver domain" VMs can provide virtual network and virtual disk backends for other VMs. KVM on the other hand is a loadable module for Linux kernel, which turns Linux kernel into a hypervisor. The difference is that in KVM all the processes (sshd, apache, etc) running on the host Linux and the VMs share the same memory address space. So KVM has less separation between the host and the VMs, by design. VMs in KVM are processes on the host Linux, not "true" separated VMs.

Re:KVM vs XEN (1)

ubersoldat2k7 (1557119) | more than 2 years ago | (#36329448)

Wish I read your explanation of Xen a few years ago. In those few sentences you explained more than in a whole 200 pages book about Xen.

Re:KVM vs XEN (5, Informative)

TheRaven64 (641858) | more than 2 years ago | (#36329710)

Not sure which Xen book you read, but the grandparent makes a lot of errors and I'd be surprised if a book was that inaccurate. Mine [amazon.co.uk] is slightly out of date, but at least was accurate at the time of printing (technical review was done by the original Xen developer).

Let's start at the end. KVM VMs and userspace Linux applications do not share the same address space. This isn't even true if you remove KVM - userspace processes have isolated address spaces. KVM requires the CPU have virtualisation extensions, which means (among other things) nested page tables. This means that there is hardware-enforced separation between the pages. The guest OS sees page tables that map from virtual to pseudophysical address space, but thinks that they map from virtual to physical. The host (Linux) sets the mapping from these pseudophysical pages to real memory pages and the CPU enforces this mapping. Xen uses exactly the same mechanism in HVM mode (it uses some other tricks in paravirtual mode).

The driver domains are correct, but it's worth noting that Xen will use VT-d or equivalent to protect against malicious use. Linux can't give a userspace program direct access to the disk controller, because if it did then a rogue DMA command could compromise the kernel. Xen will use the IOMMU to ensure that each peripheral may only issue DMAs to memory owned by the driver domain. The Solaris VM that you have accessing your block device and exporting virtual disks from ZVOLs, for example, can trample its own address space with rogue DMAs, but it can't touch any memory in other VMs.

This means that Xen (in theory) has a smaller attack profile than KVM. Xen is basically a microkernel, and it enforces low privilege on the services (OS instances) that provide drivers and the management console. With KVM, the entire kernel runs in privileged mode. It's fairly common these days for the management console domain to have either no network access, or highly-restricted access, and be separated from the driver domains. If there is a flaw in the network stack in Linux and an attacker compromises it, then with KVM they now have access to all of your VMs. With Xen, they control that driver domain, and they can inject packets into the other VMs, but they are no more able to compromise them than they would be if they controlled the router one hop away.

KVM recently gained support or live migration (this has been stable in Xen for a long time - they were doing demos of live-migrating a Quake 2 server with clients connected since the early 2000s), but it doesn't have any of the high-availability stuff that Xen 4 includes. This allows you to do things like run two instances of the same VM on different machines and transparently fail-over when one dies.

Re:KVM vs XEN (0)

Anonymous Coward | more than 2 years ago | (#36329616)

This is a fairly good explanation except strike the opening word 'secure'.

In either KVM or Xen bugs in the hypervisor (and there are and will be bugs) can allow privilege escalation. So a hypothetical elite bad guy might escape from your VM into the hypervisor and from there do anything they could do if you weren't vitualising at all.

Relying on virtualisation for security is the same error as relying on NAT for security. At best you've mildly inconvenienced the bad guys, more likely you've just increased the size of the attack surface greatly and reduced your ability to understand the threat.

Re:KVM vs XEN (3, Informative)

GPLHost-Thomas (1330431) | more than 2 years ago | (#36329036)

This why Xen [xen.org] PDF might explain it well. Under Xen, guests are running inside the host operating system. In Xen, the hypervisor starts a special Linux kernel (the dom0) that will only take care of drivers for the guests. The design is really different, and has different features. For example, in Xen, you can have your dom0 to run on 2 cores, leaving the rest for the guests (I'm not sure that is possible in KVM), and if you want to avoid any possible CPU starvation, you can even have the guests to not use the cores that the dom0 is using. The CPU scheduler is also very different (and there's not only one available...).

Re:KVM vs XEN (1)

martyros (588782) | more than 2 years ago | (#36329302)

Just what the hell is the difference between a bare iron hypervisor and KVM?

As far as Linux is concerned, a KVM virtual machine is just another process. So your whole infrastructure-critical server VMs are treated exactly the same as the random daemons that get started up as a matter of course but never used. Worse yet, the same scheduling algortihms are used -- although the VMs have to handle interrupts, while processes don't.

In Xen, there's a scheduler dedicated to scheduling VMs, and the algorithm is tweaked specifcially to deal with VMs.

Re:KVM vs XEN (3, Informative)

martyros (588782) | more than 2 years ago | (#36329412)

There doesn't have to be a battle -- there's room in the OSS world for two technologies. Xen and KVM are different technologies. For most desktop users, KVM is probably the best option; but on big servers, linux running KVM has to mix scheduling between VMs and processes. Since Xen runs VMs exclusively, it can focus only on algorithms that work well for VMs.

Re:KVM vs XEN (3, Insightful)

TheRaven64 (641858) | more than 2 years ago | (#36329716)

A lot of the Xen developers use KVM. You can run Xen and PV kernels inside KVM, which (apparently) is great for debugging. They're very different tools though. The problem is companies like Red Hat that spread a lot of FUD about Xen and tell everyone to use KVM instead, which makes about as much sense as telling them to use bash instead of vim.

I hopefully speak for lots of people when I say (1, Informative)

GauteL (29207) | more than 2 years ago | (#36328826)

... what??

Re:I hopefully speak for lots of people when I say (-1)

Anonymous Coward | more than 2 years ago | (#36328864)

Hopefully they, unlike you, know how to STFU and click the Wikipedia link in TFS.

Re:I hopefully speak for lots of people when I say (1)

asifyoucare (302582) | more than 2 years ago | (#36329016)

I think he was referring to the fact that the summary makes no sense. Perhaps 'not included' should have been 'now included'?

Re:I hopefully speak for lots of people when I say (1)

Spykk (823586) | more than 2 years ago | (#36328930)

The kernel is one step closer to achieving nirvana.

Re:I hopefully speak for lots of people when I say (1)

Robert Zenz (1680268) | more than 2 years ago | (#36329430)

So, it will be able to do cool songs, soon?

Re:I hopefully speak for lots of people when I say (0)

X3J11 (791922) | more than 2 years ago | (#36329732)

No, it means it will make shitty music and eventually shoot itself in the face.

Re:I hopefully speak for lots of people when I say (1, Funny)

NoNonAlphaCharsHere (2201864) | more than 2 years ago | (#36329190)

SAY 'WHAT' AGAIN!
Say 'what' again, I dare you, I double dare you motherfucker, say 'what' one more Goddamn time!

Re:I hopefully speak for lots of people when I say (0)

Anonymous Coward | more than 2 years ago | (#36329230)

What? Why?

Re:I hopefully speak for lots of people when I say (0)

Anonymous Coward | more than 2 years ago | (#36329354)

Trig bought a new BlackBerry!

Re:I hopefully speak for lots of people when I say (5, Informative)

martyros (588782) | more than 2 years ago | (#36329358)

What is Xen? Xen is a virtualization project that is run by four of the top five major cloud providers (including Amazon, Rackspace, &c); a commercial version written by Citrix run by thousands of sites worldwide, including large companies like Tesco, SAP, &c. It's also the approved way of running Oracle databases in a virtual machine.

What does that have to do with Linux? The Xen project is focused on virtualization. But Xen still needs to run on systems with all manner of devices. There are several ways they could have handled this. One is to try to put drivers for all of the devices in Xen. This would require a huge amount of work, mostly copying new device drivers and device fixes from Linux and porting them over to Xen. It would be a colossal waste of time: they would be duplicating effort of what Linux already does well, instead of doing what they want to do -- work on virtualization.

So what they do instead is run Xen as the hypervisor, but leverage the device drivers in Linux. They do this by creating a special VM, called "domain 0" or "dom0", which is booted first after Xen boots, that has drivers to control all of the devices. This domain is a version of Linux that is designed to be able to work with Xen to control and drive devices, while allowing Xen to control memory, CPU, and interrupts (the key hardware required to do virtualization).

Xen has been out for years. Why is this just being announced? The Xen project started out of a University research project. As is typical, they were trying to answer the question "what is possible?", and as a result, felt free to completely rip out and rewrite large sections of Linux code. This code was not upstream-able -- changes were made that were (rightly) not acceptable to the Kernel community.

Since that time, the Xen community has maintained branches of Linux with these intrusive, non-upstreamable patches, and used these branches as domain 0. At the same time, they have worked to try to get support for Linux-as-domain-0 into the mainline tree. This has been a long process, and something that has been a sore point for users of Xen for some time.

But as of Linux 3.0, all of the functionality required to use the mainline kernel tree as a basic dom0 with Xen is in. This means that if you install Xen, you'll be able to use the same kernel you booted with natively as the dom0 for Xen. It means that distributions won't have to maintain two separate kernels, one for booting bare metal, and one for booting on Xen. And it means not having to maintain the xen-linux fork, which has been a lot of painful work for the Xen community.

Re:I hopefully speak for lots of people when I say (0)

Anonymous Coward | more than 2 years ago | (#36329426)

WTF does this not have +5 Informative?

Re:I hopefully speak for lots of people when I say (3)

Kjella (173770) | more than 2 years ago | (#36329644)

WTF does this not have +5 Informative?

It does now, but slashdot seems really, really mod point starved as of late. Some discussions there looks like there's almost no one to mod, and when they do get mod points it's 5 now compared to 15 before.

No you don't (0)

Anonymous Coward | more than 2 years ago | (#36329820)

I hopefully speak for lots of people

No you don't. (PLEASE moderators, use your points on something I can actually learn from.)

Re:I hopefully speak for lots of people when I say (0)

Anonymous Coward | more than 2 years ago | (#36329908)

... what??

Slashdot. News for nerds.

Vanilla kernel on EC2 (1)

insecuritiez (606865) | more than 2 years ago | (#36328830)

Finally I get to run a newer kernel on EC2! I have been looking forward to this for months.

Re:Vanilla kernel on EC2 (5, Informative)

pasikarkkainen (925729) | more than 2 years ago | (#36328916)

Actually you have been able to run newer kernel on EC2 for a long time! Xen domU (guest VM) support has been in upstream Linux kernel since version 2.6.24. Now upcoming Linux kernel 3.0 adds Xen dom0 support, which is the *host* support, ie. Linux kernel 3.0 can run on Xen hypervisor (xen.gz) as the "management console", providing various backends (virtual networks, virtual disks) allowing you to launch Xen VMs.

Xen? Call Gordon Freeman (0)

Anonymous Coward | more than 2 years ago | (#36328898)

He has the crowbar. You will need it.

This is the reason why... (-1, Troll)

pablo_max (626328) | more than 2 years ago | (#36328912)

The very first sentence to me sums up why Linux is not successful on the desktop relative to Windows for OSx.

"...needed to run Xen as a dom0..."

Nearly every "normal" user would say, Ok, I know what this sentence means. It means this damn OS is way too complicated for people.
No use should need to know, or care about this sort of thing.

Re:This is the reason why... (2, Interesting)

Anonymous Coward | more than 2 years ago | (#36328964)

Nice try, except dom0 (Domain zero) is Xen terminology, not something linux specific.

Products such as this aren't going to be used by mainstream mom&pop users, Xen will likely not be available in boxed set at your local computerstore or gameshop. The people using this will likely always come from an IT related background.

And as for windows:
- If you run Xen with Windows, the same terminology applies (except it would be run as dom1+ since Windows doesnt support dom0 to my knowledge)
- If you open up a MCSE manual for windows you'll find a hundred other things that sound just as complicated to a layman as dom0

Re:This is the reason why... (1)

leuk_he (194174) | more than 2 years ago | (#36329212)

I Thougth i had a IT background. I Do run virtualisation product on my desktop for development purposes. I Did this even long before this was useful (For just the cool factor of running 2 OS'es at the same time).

But after 2 minutes of reading it still is not clear what Dom0 is, and what the consequences are. In fact the "domain" is not explained.

You might say that I am not expert enough, but the whole problem is that Xen might not be simple enough, failing the KISS principble.

Re:This is the reason why... (3, Informative)

Lemming Mark (849014) | more than 2 years ago | (#36329350)

It's partly historical and partly because Xen is structured differently to lots of other virtualisation systems.

"Domain" is to "virtual machine" as "process" is to "program". i.e. it's a running instance of a virtual machine. If you kill a VM and restart it, it's the same VM but a different domain. In practice VM and domain are blurred a bit when people talk, though.

Domain 0 is a bit like the host OS, but for technical reasons it's not exactly.

Re:This is the reason why... (1)

nschubach (922175) | more than 2 years ago | (#36329712)

The question I have is: Can I run Xen with my Linux dom0 and have Windows on dom1 with full GPU support and easily swap between the two so I can run my basic Linux desktop on one hand and have Windows load up and run a game in another. So far no VM solution has real capability to use full video acceleration on "guest" operating systems.

Re:This is the reason why... (0)

Anonymous Coward | more than 2 years ago | (#36329936)

No. Windows does not support being dom0, therefore doesn't use native drivers but virtual ones.

Re:This is the reason why... (1)

GPLHost-Thomas (1330431) | more than 2 years ago | (#36330016)

You could have full GPU support in Windows, using the PCI passthrough system (if your hardware is VT-d capable). But, to my knowledge, swapping between a Linux desktop using the GPU and windows using the GPU as well isn't possible. However, you can run in full screen both windows and linux, if you use the SDL driver.

For all this, it might be more easy to use Virtualbox though. Virtualbox is more adapted to the desktop environment, and when you have a Direct-X / OpenGL call in windows, it is translated into an Open-GL in your Linux (I'm not sure if it would also do that if you were running Windows as host, you'd have to check by yourself if you are interested in doing so). For that reason, Virtualbox is damned fast when it comes to read films, or play games, in a virtualized Windows. It doesn't work perfectly with all video boards though, as much as I could see.

Re:This is the reason why... (1)

Anonymous Coward | more than 2 years ago | (#36329586)

You might say that I am not expert enough, but the whole problem is that Xen might not be simple enough, failing the KISS principble.

The KISS principle applies to the implementation... NOT to your ability to understand it

Re:This is the reason why... (1)

kiddygrinder (605598) | more than 2 years ago | (#36329020)

virtualisation is complicated, maybe the article should have just said "Linux now has built in stuff to make it so you can run more than OS!", actually that's probably too complicated for most, how about "Another type of computer you don't use has built in support for running more computers inside it! it's like OSX and windows only it's another one!".

Re:This is the reason why... (1)

jimicus (737525) | more than 2 years ago | (#36329458)

IME (and I freely accept I may be utterly wrong...), all that means is the building blocks are in place to do it.

The F/OSS software for managing virtualisation is still pretty dire - if I'm being honest, it feels like someone read a VMWare feature list and decided to copy it without first ensuring they understood what all the features actually were. So they bang on about how having "feature equivalence" yet close investigation suggests that it's not as simple as that.

Re:This is the reason why... (1)

suy (1908306) | more than 2 years ago | (#36329076)

The very first sentence to me sums up why Linux is not successful on the desktop relative to Windows for OSx.

Sorry, but I find this a ridiculous point. I expect from Slashdot some degree of technical level. If Slashdot summaries had to explain everything understandable to "normal desktop users", I would had to find another place to read. Xen is not music player, and requires some knowledge. To me is a product addressed to technical people.

Re:This is the reason why... (3, Informative)

Superken7 (893292) | more than 2 years ago | (#36329086)

I'm not sure if you are trolling on purpose, or if you don't understand what this news is all about. But I'll bite.

You see, linux runs on almost any kind of hardware: from embedded systems on toasters to phones, desktop computers, laptops, to big servers. Even most supercomputers to date are running Linux. There is a _lot_ of different users that would use Linux in many different ways.

Xen is a technology that virtualizes machines, mainly intended for the data center and cloud computing environments.

This is NOT intended for users in any way. Your mom does NOT have to know that Xen even exists, just like windows users don't need to know what IIS or Apache is in order to browse the web.

Would you also say that windows and OSX is "is way too complicated for people" because you read slashdot news about some geeky kernel details about windows/OSX ?
Surely "no user should need to know, or care about this sort of thing.".

They don't. So do you about Xen. I'm not sure why someone like you is reading and posting on /., because this is usually "news for nerds", as the site indicates. :)

As many slashdotters would say about your reasoning behind your post: "You are doing it wrong." ;)

Now all I need... (3, Funny)

Suiggy (1544213) | more than 2 years ago | (#36328922)

... is 16 cores and 32 GB of RAM, and I can recompile the Kernel on Linux, encode an H.264 video on OS X, serve files via Apache HTTPD from OpenBSD, and watch streaming porn videos on Windows all simultaneously on the same machine!

Re:Now all I need... (3, Informative)

glwtta (532858) | more than 2 years ago | (#36328950)

16 cores and 32 GB of RAM

That's, uh, not exactly all that out there, these days.

Re:Now all I need... (1)

lgftsa (617184) | more than 2 years ago | (#36329240)

Yeah, the new servers I just received to upgrade our vmware cluster have 128G with only half the slots filled. Still 16 cores (2 x 8) per host, our limiting factor is having enough free RAM available for failover. The linux guests share ram nicely, but the windows guests are pigs.

Re:Now all I need... (1)

Noughmad (1044096) | more than 2 years ago | (#36329258)

16 cores and 32 GB of RAM

That's, uh, not exactly all that out there, these days.

You forgot the implied "...Beowulf cluster of..."

Re:Now all I need... (1, Funny)

dltaylor (7510) | more than 2 years ago | (#36329282)

If you're gonna stream porn on the Windows guest, instead of something useful like original Star Craft/Brood War, keep your clean guest image for reloads. You're better off streaming the porn on a Linux guest, since the embedded malware is much less likely to run.

Re:Now all I need... (1)

petermgreen (876956) | more than 2 years ago | (#36329384)

It depends whether he means 16 good cores or 16 shitty cores ;)

Yes both intel and AMD sell CPUs that let you put 16+ cores in one machine BUT afaict in both cases the individual cores are substantially slower than you can get in a 12-core (2x6) xeon 56xx machine. The prices are also pretty crazy afaict.

Re:Now all I need... (2)

Rockoon (1252108) | more than 2 years ago | (#36329958)

CPU loadout prices and performance metrics for various setups [cpubenchmark.net]

The 12-core X56xx's solutions arent touching the 48-core solutions from AMD as of yet in parallel workloads. The Opteron 6168 solution is cheaper with more performance and the Opteron 6174 route is more expensive but significantly faster over-all, than a pair of X5690 priced at $3300+

I am simply amazed that Intel has not taken its older designs for larger process sizes and simply packed on more cores during a process reduction in order to break AMD's knee's in this market. Instead they are only using even more transistors per core and not upping the core count. That strategy is OK for desktop chips but the virtualization crowd that is running dozens of servers on one box are better off with more cores.

Not that AMD has produced anything stellar recently (tho Bobcat is certainly a formidable Atom competitor while Bulldozer is rumored to be postponed due to serious performance issues with the current stepping) but Intel still doesnt offer any competition in the big virtualization arena vs AMD's several-year-old solutions.

Re:Now all I need... (1)

dbIII (701233) | more than 2 years ago | (#36329874)

48 cores (4 sockets with AMD 12 core) and 64GB here and it was only around $10K. There are a lot of much bigger machines around - that's effectively just an overgrown gaming machine these days which is why economies of scale brought the price down to something sane instead of Sun or IBM prices. I've seen people spend as much on two laptops.
It's not for virtual machines. The stuff it runs works properly in parallel but runs faster on one machine with shared memory than it can on a cluster.

Meanwhile (4, Interesting)

TheRaven64 (641858) | more than 2 years ago | (#36328932)

Xen Dom0 support has been supported in released versions of NetBSD and Solaris for something like 4 years, while the VMWare lobby on the LKML was requiring the entire paravirtualisation subsystem to be rewritten before they'd accept patches, and Red Hat decided to push KVM as a Xen replacement, in spite of them having very different capabilities.

Largely irrelevant though (3, Insightful)

buchanmilne (258619) | more than 2 years ago | (#36329344)

... as most users don't use vanilla upstream kernels. And, most distributors / distros have a supported release which provides Xen Dom0 support (including Red Hat).

Re:Largely irrelevant though (1)

pasikarkkainen (925729) | more than 2 years ago | (#36329396)

.. Most users end up using "upstream kernels" when their distros release new version with new kernel.. Distros like Ubuntu and Fedora release two times a year so they don't want to do custom porting of patches, they want all the features to be in upstream Linux kernel. Linux distributors like Redhat have "upstream first" policy, which means features need to be in upstream Linux kernel before they can be included (backported) to products. So when Xen dom0 support is now in upstream Linux kernel it means most distros can actually ship it easily!

Re:Largely irrelevant though (1)

cynyr (703126) | more than 2 years ago | (#36329740)

hmm, since the new kernel dev model(2.5.x basically) I've been running vanilla kernels, or at least distros that do not require the huge custom patch sets... ahh the good old days of redhat 7.2, and suse 6....

Re:Meanwhile (1)

Lemming Mark (849014) | more than 2 years ago | (#36329362)

Xen support got into NetBSD and Solaris more easily, I think, because influential individuals pushed it in there whereas the Linux community had lots of quibbles over the patches and how they should be done correctly. The debate with VMware was a bit confusing and didn't help things get done quickly. RH and IBM and SuSE and others were behind Xen originally but that has gone a bit quieter subsequently.

Part of all of this, though, is due to the Xen team having different priorities to most of those other organisations - especially whilst setting up their own Windows-focused virtualisation product. There's a fair degree of difficult personalities on the Xen and Linux sides too which probably didn't help things go smoothly.

Re:Meanwhile (5, Informative)

zefrer (729860) | more than 2 years ago | (#36329400)

Just had to reply to this.. Sun forked Xen 3.1 something like 4 years ago, yes. That same fork, Xen version 3.1 is what is still being used today in Solaris and Sun had previously (pre-buyout) said they would not merge to any newer versions of xen.

So while Solaris can claim Xen Dom0 support it is no where near the capabilities of current Xen 4.0 and with no plans to update you're stuck on 3.1 with support only coming from, now, Oracle. Yeah, awesome.

Re:Meanwhile (1)

pasikarkkainen (925729) | more than 2 years ago | (#36329474)

Remember Xen hypervisor (xen.gz) is a separate piece of code. Kernel (Linux, BSD, Solaris) support for Xen dom0 is another thing. So if someone wants, they could run *Solaris dom0 kernel on Xen 4.1 even if Oracle does not ship it. It might require some work to get the *Solaris dom0 kernel working properly with newer Xen version. Oracle itself has focused on OracleVM, which is their Xen-based virtualization product, using Linux as dom0. You can run Solaris VMs on OracleVM/Xen, of course.

Re:Meanwhile (4, Informative)

diegocg (1680514) | more than 2 years ago | (#36329780)

'VMWare lobby', WTF? The real problem were things like this [lkml.org] and this [lkml.org]:

The fact is (and this is a _fact_): Xen is a total mess from a development
standpoint. I talked about this in private with Jeremy. Xen pollutes the
architecture code in ways that NO OTHER subsystem does. And I have never
EVER seen the Xen developers really acknowledge that and try to fix it.

Thomas pointed to patches that add _explicitly_ Xen-related special cases
that aren't even trying to make sense. See the local apic thing.

So quite frankly, I wish some of the Xen people looked themselves in the
mirror, and then asked themselves "would _I_ merge something ugly like
that, if it was filling my subsystem with totally unrelated hacks for some
other crap"?

Seriously.

If it was just the local APIC, fine. But it may be just the local APIC
code this time around, next time it will be something else. It's been TLB,
it's been entry_*.S, it's been all over. Some of them are performance
issues.

I dunno. I just do know that I pointed out the statistics for how
mindlessly incestuous the Xen patches have historically been to Jeremy. He
admitted it. I've not seen _anybody_ say that things will improve.

Xen has been painful. If you give maintainers pain, don't expect them to
love you or respect you.

So I would really suggest that Xen people should look at _why_ they are
giving maintainers so much pain.

                Linus

BTW, I have absolutely no doubt that NetBSD and Solaris merged Xen faster than anyone else.

Re:Meanwhile (0)

Anonymous Coward | more than 2 years ago | (#36329986)

Can you elaborate on what different capabilities Xen And KVM have?

FreeBSD Xen support (2)

simoncpu was here (1601629) | more than 2 years ago | (#36328954)

Dear FreeBSD,

When will you ever have a Xen dom0 support?

Thanks,

Charlie Root
FreeBSD Fanboi

Re:FreeBSD Xen support (1)

pasikarkkainen (925729) | more than 2 years ago | (#36329030)

At the Xen Hack-a-tron event in March there was some discussion/updates about Xen+FreeBSD.. I can't remember the details, but you might want to ask on xen-devel mailinglist.

Re:FreeBSD Xen support (0)

Anonymous Coward | more than 2 years ago | (#36329526)

Keep an eye or twelve on http://lists.freebsd.org/pipermail/svn-src-projects/2011-May/003972.html

Now can we get Oracle/Redhat/Citrix (1)

Mongo (7168) | more than 2 years ago | (#36328968)

To dedicate resources to producing a good cluster LVM lock manager that does not depend on CORAID?

Something like SGI's CXVM would be great!!!

Got confused (1)

Anonymous Coward | more than 2 years ago | (#36328980)

.. thought for a moment the titles says Linux 3 will have full XMen support!

Will it cook me dinner? (0)

dutchwhizzman (817898) | more than 2 years ago | (#36329110)

So what exactly makes this so special? It's a step for one of the many virtualization solutions in the market these days.

I for one wouldn't trust Oracle with any part of my infrastructure if I can help it. Citrix to me still is a company that makes an expensive Xclient for MicroSoft products and a niche product they bought, Xen, with no apparent synergy with their windows products, and who else really cares?

Re:Will it cook me dinner? (2)

pasikarkkainen (925729) | more than 2 years ago | (#36329138)

Remember Xen hypervisor is opensource (GPL), just like Linux kernel, so all the Oracle and Citrix code in the hypervisor and in the kernel is opensource. Citrix uses XenServer as a platform to run their other products, and obviously Xen is the best platform to run those Citrix "windows products". Novell ships Xen in Suse Linux Enterprise (SLES) 10 and 11. Debian ships Xen in their current version. I heard Ubuntu is going to add Xen back now when the kernel components are included in upstream Linux. Fedora ships Xen aswell. Not to mention majority of the cloud (Amazon EC2, Rackspace, etc) are running Xen.

Re:Will it cook me dinner? (1)

Enter the Shoggoth (1362079) | more than 2 years ago | (#36329378)

So what exactly makes this so special? It's a step for one of the many virtualization solutions in the market these days.

I for one wouldn't trust Oracle with any part of my infrastructure if I can help it. Citrix to me still is a company that makes an expensive Xclient for MicroSoft products and a niche product they bought, Xen, with no apparent synergy with their windows products, and who else really cares?

Bingo!

Dont trust anything for Oracle or Ellison & Co (0, Interesting)

Anonymous Coward | more than 2 years ago | (#36329134)

This is the worst company ever and Larry Ellison is greedy. If you are a Sun workstation owner read below:

http://www.newser.com/story/76753/americas-greediest-people.html

America's Greediest People
Larry Ellison heads up a list full of no-good rich folks
By Kevin Spak, Newser Staff

Posted Dec 23, 2009 2:12 PM CST

        STORY
        COMMENTS (36)

Email Share

(Newser) – These days, it’s easy to fill up a “greediest Americans” list. Just ask TooMuch.org, a site devoted entirely to “excess and inequality.” “We could fill an entire top 10 just with bankers from Goldman Sachs,” it boasts. The list:

        Larry Ellison: The really galling part isn’t the fortune he spent on his yacht—including $10 million for the mast alone. It’s that the Oracle CEO contested the $166.3 million tax appraisal on his mansion, ultimately costing local schools $250,000 a year.

        Richard Scott: Scott, CEO of Columbia/HCA Healthcare Corp. during its Medicare fraud scandal, led the year’s media blitz against Democrats’ health care reform efforts.
        Mark Hurd: Hewlett-Packard’s CEO jacked up ink prices, while firing 6,000 workers and cutting salaries. He, meanwhile, took home $26 million.
        Rupert Murdoch: One day, while cruising on his $30 million yacht, Rupert decided to start the drumbeat to charge for newspaper articles. Probably because his annual take-home from News Corp had fallen to a meager $27.5 million.
        For the full list, click the link above.

Did you know M$ is a Xen partner? (1)

Anonymous Coward | more than 2 years ago | (#36329554)

http://www.informationweek.com/news/190500358

Re:Did you know M$ is a Xen partner? (1)

Lennie (16154) | more than 2 years ago | (#36329672)

Actually they sponsored (a large part ?) the research at the univerisity when Xen was created.

Re:Did you know M$ is a Xen partner? (0)

Anonymous Coward | more than 2 years ago | (#36329826)

This is why Hyper-V is so similar to Xen.

xen will set you free, again. (-1)

Anonymous Coward | more than 2 years ago | (#36329684)

f-uck da cops i go supa star props.

So Linux 3.0 got its major feature after all (1)

cronius (813431) | more than 2 years ago | (#36329828)

Just when Linus finally started convincing people that Linux 3.0 would be a "normal time based release" with "no major changes" they whip this milestone feature out from under the rug.

Xen out of the box? Linux 3.0.

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