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Desperately Seeking Xen

kdawson posted about 7 years ago | from the whither-the-gorilla-killer dept.

Linux Business 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."

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192 comments

Need a special processor (0)

flyingfsck (986395) | about 7 years ago | (#19675795)

Xen only works with specific hardware which I don't have. Sooooo, back to VMware.

Re:Need a special processor (4, Informative)

Mostly a lurker (634878) | about 7 years ago | (#19675871)

It is true that Xen requires special hardware to legally run MS Windows. It is also better for performance, generally, to have such hardware. However, there is nothing stopping you from running Xen on pretty much any computer you are likely to own as long as the VMs are Linux based.

Re:Need a special processor (1)

flyingfsck (986395) | about 7 years ago | (#19677299)

Yup, I need the ability to run Win 2003 Server on a VM and the only way I could make that work was with VMware. Win 2003 crashes Qemu and Virtual Box and needs a special processor for Xen.

One funny I found with VMware Server is that it cannot run RedHat RHEL version 5. The install proceeds partly then screws up.

Each and every VM system has a bunch of quirks, so one has to try the lot to find a good one for your purpose.

Re:Need a special processor (1)

TheRaven64 (641858) | about 7 years ago | (#19677427)

However, there is nothing stopping you from running Xen on pretty much any computer you are likely to own as long as the VMs are Linux based
You mean 'Free Software,' rather than 'Linux based.' You can run NetBSD, FreeBSD, Linux, OpenSolaris, Minix or Plan 9 (maybe some others I've forgotten) as paravirtualised domU guests with no special hardware. You can also run OpenSolaris or NetBSD instead of Linux in domain 0, if you don't feel like running Linux. Which makes me wonder slightly what this is doing in the 'Linux' category...

Re:Need a special processor (1)

mwilliamson (672411) | about 7 years ago | (#19675911)

VirtualBox doesn't require any special hardware.

Re:Need a special processor (1)

friedman101 (618627) | about 7 years ago | (#19676003)

VirtualBox (http://www.virtualbox.com) has an open source edition of their virtualization software which is easy to use, cross platform, and works well on my machine. It can also read vmware disk images which should make transitioning pretty painless. The closed source (but still free as in beer) version also supports USB and simple file sharing between guest and host. I'm currently using it to run Windows XP inside my Vista machine to take care of compatibility issues.

Re:Need a special processor (1)

tropicdog (811766) | about 7 years ago | (#19677497)

I think you mean VirtualBox.ORG, not com.

Xen (and virtualization) is for the Enterprise (4, Insightful)

xzvf (924443) | about 7 years ago | (#19676325)

While it might be nice if all these things are easy and work well for the hobby crowd, the real money in virtualization is in the enterprise space. Most servers in enterprise environments run 15% max and are refreshed every 3-5 years. The special processor matters less in that case, and the competition is between a mature VMWareESX server (not free), a hardware based IBM and Xen. Microsoft is a surprisingly minior player. VMWareESX server is very good for x86 consolidation and saves customers money, but is very expensive. It is still the best option for Intel based consolidation. Xen has deep penatration in enterprise lab environments. It is just getting the enterprise management tools to move into real production. IBM is very good at virtualization and stability, but on proprietary power and mainframe hardware. Xen will be fine, because the market is very immature, but expect more seamless and non-attrusive virtualization on the desktop.

Re:Xen (and virtualization) is for the Enterprise (1)

b0r1s (170449) | about 7 years ago | (#19676515)

A couple notes ....

  1. Microsoft is becoming a bigger and bigger player by the day. I know one managed service provider who's pushing virtually every client onto MS Virtual Server whether they ask for it or not.
  2. Virtualization is selling a LOT of units in the hosting industry, and as people realize how convenient it can be, it's moving to smaller shops
  3. Shit like Virtuozzo / OpenVZ seems to get ignored because it's so hosting centric - there's a hell of a business model to be made in turning something like SW-Soft's VZ management suite into an enterprise product rather than a hosting-centric billing/support control panel.


But what do I know, I just do this for a living.

Re:Xen (and virtualization) is for the Enterprise (1)

xzvf (924443) | about 7 years ago | (#19677973)

Good points. Hosting companies are leaders in the virtualization market, and most of what I was talking about before was large enterprises consolidating. I have a limited field of vision on this issue, but I just don't see the buzz around the MS offerings with big customers. I think we have some emerging contenters in the virt market, like KVM and VZ and maybe even Sun's containers. What would be great is an overarching enterprise level management tool that takes advantage of the various hypervisors (container, guest) to use the best in the correct situation. We also need improvements in the network infrastructure to make is far more flexible and dynamic when moving VM's around.

Re:Xen (and virtualization) is for the Enterprise (1)

Dorkmunder (950796) | about 7 years ago | (#19678601)

Yes, Xen is becoming a great tool for hosting companies, making it very easy to offer customers quickly scalable resources (look at www.engineyard.com for an exmaple on Xen on Gentoo with Mongrel and Rails IIRC). It has also become a great resource for me in a University setting where VMWare is just too dang expensive. We run Xen on Debian and then "guest" all sorts of OS'es (yes, we have the right processors to make Win2003 work). On the down side, they still have some work to do to make multiple virtual volumes a possibility plus they need to have a way to migrate guests from server to server across a SAN (right now you need to do an export\import vs. VMWare's VMotion app. Supposedly all of this is coming this year in the next version (3.3? or 4?). Anyway, I have found the performance to be excellent and the cost right.

vm ware (0)

Anonymous Coward | about 7 years ago | (#19675807)

vm ware is feature king at the moment - but competition is a good thing.

If you want to run multiple linux instances on the cheap then xen is the way to go at the moment.

Re:vm ware (1)

Anarke_Incarnate (733529) | about 7 years ago | (#19675915)

Virtual Iron has some features,that are important that VMware does not :)

Re:vm ware (1)

Em Ellel (523581) | about 7 years ago | (#19675985)

Virtual Iron has some features,that are important that VMware does not :)
Can you expand on this? I never even heard of Virtual Iron before just now, what useful features does it have over XEN/VMWare?

Thanks

-Em

Re:vm ware (1)

Anarke_Incarnate (733529) | about 7 years ago | (#19676319)

Virtual Iron uses Xen but does not do para virtualization. It supports 8 CPUs per guest and is a "bare metal" VM hypervisor (does not require a host OS).


It also comes with the ability to move virtual machines from host to host (based on pools of resources) either by some threshold being met (say, 75% CPU utilization on a Dell PowerEdge server moves it to an HP Proliant which is only 45% utilized ) without the virtual guest OS ever skipping a beat. Vmware does this with VMotion, but that is an add on package. Virtual Iron also supports raw devices presented from a SAN and can boot the "Hypervisor OS" from SAN as well. It supports Microsoft's disk format and there are free tools that can convert VMware disk images into that format so any Virtual Appliance built for VMware can be used in Virtual Iron (and no, I don't work for them).


However, because it uses Xen and does not do para virtualization, AMD-V or Intel VT must be available on the CPU being used. My plan was to use VI on Sunfire X4600 M2s with 16 cores available and the capacity to have 256GB RAM and 4 built in GigE (with slots enough for more GigE and Fibre Channel).


Check out their demo on their website

Re:vm ware (1)

b1ufox (987621) | about 7 years ago | (#19676371)

Ok, Virtual Iron is exclusively for Vt-x and SVM enabled processors.

This means it makes use of the hardware assisted virtualization provided by these two techniques by Intel and AMD respectively.

Xen on the otherhand takes a paraivirtualization approach. It includes a hypervisor which shields the hardware access from guest domains(unless you are running a driver domain).

So Virtual Iron can run unmodified guests from its first release, as opposite to Xen which started in era when there were no SVM and Vtx capable processors

So, you cannont strictly say adavntage over Xen.

OTOH Xen though predominantly a PV hypervisor can still make use of VTx and SVM processors, to run unmodified Guest Operating Systems but performance hit is there.

So, Xen is a great product which needs a lot of grooming before it can be considered a dependable virtualisation solution.

It is better than VmWare in the sense of end usability, and that means throughput, latency and responsiveness.

Re:vm ware (1)

Anarke_Incarnate (733529) | about 7 years ago | (#19677447)

The benefit are enterprise level features that exist right now that Xen does not have in the F/OSS version. The "Commercial" version will have those features very soon, if not already. Many large companies WILL NOT allow modified kernels or modified guests in general to be released into production. The lack of support for older CPUs that do not have built-in virtualization is the reason I cannot use Virtual Iron just yet for my company, but I am pushing them towards different machines for the future. I see that as an uphill battle because they are on a blade vendor that does not support those chips right now. I wish we could just dump that in general and just go to Sunfire X4600s.

Re:vm ware (1)

caluml (551744) | about 7 years ago | (#19676995)

Commas are, like violence - you, can always use, more to solve a problem.

Re:vm ware (1)

Em Ellel (523581) | about 7 years ago | (#19675943)

vm ware is feature king at the moment - but competition is a good thing.

If you want to run multiple linux instances on the cheap then xen is the way to go at the moment.
Not that I disagree that OSS and competition is a good thing but what am I missing here? Last I checked VMWare Server product was free - so how much cheaper than free can you get?

-Em

Re:vm ware (1)

stoolpigeon (454276) | about 7 years ago | (#19675971)

server (free) and esx (expensive (to me anyway)) are very different products, and many of the really attractive features exist only in esx.

Re:vm ware (1)

CastrTroy (595695) | about 7 years ago | (#19676183)

Could you outline some of the features on ESX that you find really attractive? As a home user, I find that VMWare server fits just about all my needs.

Re:vm ware (1)

Em Ellel (523581) | about 7 years ago | (#19676305)

The major things that makes ESX attractive as far as I know all have to do with Enterprise usage - i.e. bare metal hypervisor (self contained "Host" OS) and ability to live transfer a VM from one server to another via shared storage without shutting down.

Can't see this impacting a home user, unless I am missing something.

-Em

Re:vm ware (1)

stoolpigeon (454276) | about 7 years ago | (#19676385)

Right - there is an intersection here of two completely different user groups - I belong to both myself. I use vmware server on my personal/work machine - so that I can have xp available for a couple windows only apps that I must use. In the datacenter we use a mix of aix virtualization on p5s and esx. virtualization in the datacenter is bringing our organization a number of benefits that server can't provide. My understanding is that one feature is moving virtual machines from one host to another on the fly. There are probably more - but I'm a dba so I'm at the edges of this stuff.

Re:vm ware (1)

Tony Hoyle (11698) | about 7 years ago | (#19678139)

ESX is a bitch to get working. We got a demo, set up a machine with hardware entirely on VMWare's 'approved' list - and it wouldn't install because it was missing drivers. VMWare couldn't help because we hadn't parted with any money yet... we went with RHEL w/ the free VMWare server which 'just works' (xen doesn't have the I/O performance to be deployed seriously yet).

Re:vm ware (1)

BagOBones (574735) | about 7 years ago | (#19678407)

Who is your hardware vendor? Out of the box ESX ran on both the server and the SAN we where using with NO extra drivers.

Re:vm ware (1)

CastrTroy (595695) | about 7 years ago | (#19678493)

Transfering a live server could be useful at time I guess, although like you said, probably not necessary for the home user. Also, I was aware of the "bare metal hypervisor", which I guess probably has quite a few advantages, since just the host OS can eat up a lot of the machine resources. How bare of a Linux machine can you run VMWare server anyway? You can run Linux itself with very little resources, It should be possible to create a distro that's cut down to just the stuff necessary to run VMWare.

Re:vm ware (4, Insightful)

Per Wigren (5315) | about 7 years ago | (#19676015)

If you want to run multiple linux instances on the cheap then xen is the way to go at the moment.
Except that OpenVZ [openvz.org] is a better way to go in that case. If you are only going to run multiple instances of Linux, with OpenVZ you don't need to preallocate a fixed amount of memory for each VM, the root filesystem can be a subdirectory of the root OS instance's filesystem, among many other things. It can do just about everything that XEN can do, including live migration to other physical nodes.

Re:vm ware (4, Informative)

gtrubetskoy (734033) | about 7 years ago | (#19676279)

Except that OpenVZ is a better way to go in that case.
For fairness it should be mentioned that aside from OpenVZ there is also Linux VServer [linux-vserver.org] which does a few things better than OpenVZ (though OpenVZ does some things it does not). Our preference has always been VServer, it's a well-run project with emphasis on quality and well thought through design rather than quantity.

Re:vm ware (1)

neonux (1000992) | about 7 years ago | (#19677369)

Linux VServer is also quite easier to configure/maintain compared to OpenVZ imho :)

Re:vm ware (1)

a1mint (1021941) | about 7 years ago | (#19677571)

I use vserver all the time, I like it.

I wish the /etc/vserver directory and the excessive symbolic links weren't all over the place though. The configuring I find a little convoluted.

Timely for me! (1)

grub (11606) | about 7 years ago | (#19675857)

Just yesterday I wrote in my journal asking for VM advice. Sadly it seems none support 3D cards very well.

Re:Timely for me! (1)

Dutchie (450420) | about 7 years ago | (#19675959)

True. This is a major problem IMO. Once upon a time I had hoped that I could run VM's *and* have full 3D support, both in a Windows VM and a Linux VM.

Turns out that 3D accelerated is not an option right now, but Xen was at that time working on something that could (given the right hardware, which at the time was only high end IBM mobo's) isolate PCI cards completely.

That way, you could have two graphics boards in your system, and when Xen starts up it could assign one graphics board to, for example, a Windows VM which could then run 3D accelerated drivers with it's native drivers.

I wouldn't quite give up on Xen yet :)

Re:Timely for me! (1)

mrchaotica (681592) | about 7 years ago | (#19676109)

IIRC, the latest (i.e., so-called "Direct3D 10 compatible") graphics cards have MMUs, which would (theoretically) allow multiple OSs to share the card in the same way that they can currently share the CPU.

Re:Timely for me! (3, Informative)

TheRaven64 (641858) | about 7 years ago | (#19677541)

There was some interesting work presented at the XenSummit which should be making it into the main tree eventually on 3D support in Windows. The idea was that the memory layout was adjusted slightly so that Xen and dom0 lived nearer the top, and Windows in an HVM domain lived at the bottom. This allowed Windows to use existing 3D drivers, without having to do any address translation when performing DMAs (not an issue if you have an IOMMU, but hardly anyone does yet).

The problem with giving access to hardware to guests at the moment is that without an IOMMU, any DMA request the driver issues will read or write memory from a physical address indicated by the driver. In a virtual machine, what the driver thinks is a physical address is actually a virtual address. This means a DMA request will read from or write to an arbitrary memory location. By putting the HVM guest at the start of memory, this translation is the identity function, so the driver will work. The only downside is that you lose protection from other domains; a malicious driver can still damage your other VMs or even the hypervisor.

Re:Timely for me! (1)

stoolpigeon (454276) | about 7 years ago | (#19676007)

I just think at this stage in the game, as the article implies, the primary focus is the datacenter. And 3d just doesn't matter there in the vast majority of the cases. Certainly not enough to make 3d a top priority.

VirtualBox performance (2, Interesting)

mwilliamson (672411) | about 7 years ago | (#19675883)

It seems that VirtualBox.org's product, fully virtualizing a copy of XP on my non-VT machine under a linux host OS, totally runs circles around Xen even on VT hardware as far as performance is concerned. Integration into the host enviroment is also quite beautiful. Why is there seldom a mention of VirtualBox in this arena?

Because.... (2, Interesting)

Ayanami Rei (621112) | about 7 years ago | (#19675981)

virtual box is basically QEMU with a much better KQEMU component that they developed on their own. This isn't very interesting because this is the same thing as VMWare or any other closed source Ring0-in-Ring1 emulation using polymorphic code.

Re:VirtualBox performance (1)

jsailor (255868) | about 7 years ago | (#19676895)

I can't comment on why VirtualBox doesn't get more press, but I can confirm that I've had very good results using VirtualBox 1.3.x on fairly low powered machines. My guess is that it gets lumped under QEMU when comparisons are made.

Parallels (1)

queenb**ch (446380) | about 7 years ago | (#19677487)

Parallels, which is a commercial product, is one of the slickest VM's I've seen for desktop use. No one ever mentions them, either.

2 cents,

QueenB.

Re:VirtualBox performance (1)

drinkypoo (153816) | about 7 years ago | (#19677615)

Why is there seldom a mention of VirtualBox in this arena?

I just installed virtualbox on Ubuntu Feisty to see what your fuss was about. I tried to install Windows 2000 in a VM and VirtualBox wouldn't let me type F8 to accept the license. No idea whose fault that is, but speaking for myself I can say only that vmware server 'just works' and thus I have no reason to use virtualbox, which does the same things but not as well.

don't know v. Xen, but generally (1)

colourmyeyes (1028804) | about 7 years ago | (#19677805)

VirtualBox is really nice; I don't know about the performance comparison to Xen, but VirutalBox is a breeze to use and performance is generally pretty good. I've been messing with VM software for about six or seven years and just discovered VirtualBox a few months ago. Before that I had heard of Bochs, Plex86, Xen, VMware, VirtualPC, Parallels, and Qemu (off the top of my head). Where has VirtualBox been hiding?

Nice Article (1)

stoolpigeon (454276) | about 7 years ago | (#19675925)

Not just for xen - but if you are interested in virtualization in general. Lots of links to many other products - open and closed. So if you aren't into xen, but still want to know about what is going on in this space (to some extent - they don't even touch the stuff IBM is doing really) then it's worth the time.

KVM vs. Xen (1)

aztechClanIII (536891) | about 7 years ago | (#19675941)

I am also a VMWare fan and was very happy when they released VMWare server for free a while back. I use VMware Server every day to run a Windows XP machine and Ubuntu Server in a virtual networked environment which I develop client/server apps on. It works awesome.. although I long for faster hardware emulation.

I'm rooting for KVM to take over, however it probally needs some time to settle down. Networking is harder to setup, and I've noticed graphical glitches in winXP.

what went wrong is (1)

advocate_one (662832) | about 7 years ago | (#19675995)

you can't run Windows using Xen as Microsoft won't let you recompile the windows kernel... and this ability of being able to run windows on Linux is one of the things Microsoft allows to be done with the blessed versions of Linux for corporate customers. Normal mortals can't do it and will never be able to do it.

Personally, I don't give a flying fig about being able to run Windows or windows programs on Linux... there isn't anything I want to do on windows that I can't do on Linux... (note the emphasis, I find everything I need in Linux...)

Re:what went wrong is (5, Informative)

stevey (64018) | about 7 years ago | (#19676079)

Not true.

If you have VT-capable hardware then you can run Windows under Xen. You do need the hardware to support it though, and that is a problem for some home users. Recent AMD and Intel chips have slightly differing VT support but both work.

I run Xen at home along with xen-tools [xen-tools.org] (which I wrote) to easily create new Debian guests on demand. These are used for software testing, hacking, and general service isolation.

I think Xen is just now reaching "mainstream" in the sense that you don't have to be an early adoptor or major tinkerer to get it working. Now that distributions are including Xen kernels in their newer releases it really us available for all.

Re:what went wrong is (-1)

advocate_one (662832) | about 7 years ago | (#19676159)

last I knew, you had to have a recompiled windows kernel to be able to run windows using Xen. Linux is easy on Xen, Windows is the problem

Re:what went wrong is (2, Informative)

Anonymous Coward | about 7 years ago | (#19676369)

Yes, but as he already told you, what you know is out of date. You can run an un-modified Windows on top of Xen provided your hardware supports the Intel or AMD VT extensions.

Re:what went wrong is (1)

pinkocommie (696223) | about 7 years ago | (#19676363)

I've been messing with XEN for a week or two, thought it would help me out with debugging and maintaining multiple systems without the need for them. Picked up an AMD SVM CPU and tried it, running into a wall. The XEN list serv wasn't much help nor were the log files. In comparison Virtual PC 07 / VMWare on Windows worked flawlessly on the first try... I'd still prefer using XEN and might take a stab at KVM but wasting a week just to get to the boot screen without success was a little painful. FYI I tried CentOS and WinXP

Re:what went wrong is (1)

DataSpring (757974) | about 7 years ago | (#19677115)

In addition, you can achieve very good performance with Windows on Xen (utilizing VT/SVM processors) if you also install the Xen Paravirtualized drivers under Windows, once you have the base OS installed. You can get these drivers in the XenServer edition on the xensource.com site. (Actually, I think my coworker got the drivers running in the XenExpress edition.)

In any case, performance was significantly better with the PV drivers - in fact, when we first installed a copy of Windows under Xen, disk performance was so bad that a five-year old machine that is overloaded was serving up a website faster than the virtualized version of Windows. After we installed the PV drivers (and rebooted the Windows VM,) performance was near native (we have two of these servers, and were doing exhaustive tests on both at the same time using both benchmarking tools and real-life tests, one had Windows installed natively, one had Xen + Windows.)

After further testing, we were so impressed, we put it into production. On the Xen machine, there are two Windows guests and one Linux guest. Windows 1 hosts the Asp.NET website, Windows 2 hosts MS SQL Server 2005 Express, and the Linux VM hosts DNS services. There are real-world websites running on this platform and performance is great. Notice, I didn't say "adequate" or "good" - it really is great, and we plan to put four more servers into production with a similar type of configuration for various purposes.

Re:what went wrong is (1)

Tony Hoyle (11698) | about 7 years ago | (#19677991)

I hope you paid for that xenserver....

I've tried them and the performance still isn't great - xen seems to have bottlenecks on its network and disk I/O that are a result of using qemu to do it in software... the maximum net throughput even on PV is a fraction of a 100mb link let alone a gigabit one, and my old 486 firewall does faster disk access.

Re:what went wrong is (0)

Anonymous Coward | about 7 years ago | (#19678263)

On throughput tests of Win2k3 with the PV drivers, I've been able to max out a gigabit link. Compared to bare metal, there is a slight performance degradation.

I don't recall what the disk I/O performance was, but it was pretty good too.

Xen kernels are nearly useless (1)

r00t (33219) | about 7 years ago | (#19677561)

Again, virtualization is for running Windows. Not Linux!

Yeah, sure, there are a few weirdos out there.

For most of us, there is no point in running Linux under Xen. We already gave Linux the native hardware. I guess somebody might want to run a Linux guest on Windows, but that'd be Wrong and is anyway unsupported.

When I want to run a Linux app, I just run it. No problem. When I want to run a Windows app, I need virtualization.

Xen is thus a solution in search of a problem.

Re:Xen kernels are nearly useless (1)

Anarke_Incarnate (733529) | about 7 years ago | (#19677791)

Of course!! Why would somebody want to buy big hardware like a Sunfire X4600 M2 with 16 cores, 256GB RAM, 4GbE and multiple I/O slots to run multiple instances of Linux and/or Windows and/or BSD, and/or Solaris x86 when they could just run 1 instance and let the computing power of their server be use damn inefficiently?

Nobody wants to make their data center streamlined and efficient for use of power and cooling, which in many ways costs more than the initial hardware purchase over a 4yr refresh cycle....


/sarcasm

Re:Xen kernels are nearly useless (1)

stevey (64018) | about 7 years ago | (#19677843)

That might be true for you, but not for other people.

I run Debian unstable upon my desktop, but if I want to build Debian packages suitable our the Stable release, or even CentOS5 RPMs and SuSE RPMs, what should I do? I could use chroot(), or I could use virtualisation. That latter is what I do, because it is more "real" and allows me to run X, etc.

There are many times when it is useful to run distinct copies of Linux upon one host, for example a hosting company giving user's their own "real" system, to build packages for multiple distributions, to test software without messing up your development system, automated testing systems, and more.

Yes you can do that without virtualisation, but sometimes it isn't as neat.

Re:Xen kernels are nearly useless (1)

DrSkwid (118965) | about 7 years ago | (#19678275)

There are more OSes than Windows & Linux

Re:what went wrong is (1)

postbigbang (761081) | about 7 years ago | (#19676429)

Wouldn't it be nice if you could get a Xen rootkit for Windows XP and/or Vista?

Perhaps it's a silly concept, but it could make work easier.

But then there's the graphics difficulties.... the need for a hyperthreading CPU....and there's no support of course, for a rootkit ;)>

Host OS the one with better drivers (2, Interesting)

interiot (50685) | about 7 years ago | (#19676001)

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)

Pointless? (1)

ichigo 2.0 (900288) | about 7 years ago | (#19676203)

Then what's the point? What special applications does Linux have that require you to run it in a VM on Windows?

Usually people run Windows in a VM because they have some app that just doesn't exist on Linux, but that can hardly be the problem as most Linux apps are OSS and thus portable to Windows.

Re:Pointless? (1)

gbjbaanb (229885) | about 7 years ago | (#19676431)

I think you have that slightly wrong - when you say "Usually people run Windows in a VM", I think you meant to say "Usually people run Windows".

Some of them will take the plunge into the uncharted waters by running Linux in a VM so it won't trash their desktop settings, apps etc, ut make no illusion that the majority of people using computers are using Windows, not Linux.

Re:Pointless? (1)

ichigo 2.0 (900288) | about 7 years ago | (#19676743)

Sorry to rain on your parade, but what I meant was that the reason people (who aren't on Windows) run Windows in a VM is because they need it for some app. Obviously people who already are on Windows have no need to run it in a VM.

Why not use a live-cd if one wants to test it without committing? The inherent slowness of VMs makes it difficult to ascertain how well Linux would run, and the lack of 3d-acceleration means that none of the shiny things that draw in new people will function.

Re:Pointless? (1, Offtopic)

CastrTroy (595695) | about 7 years ago | (#19677129)

I just can't wait till KDE4 is ready. Then I can have Amarok, Kopete, and most importantly Digikam running on windows. Hopefully it's stable, and runs well.

Re:Pointless? (1)

interiot (50685) | about 7 years ago | (#19677401)

that can hardly be the problem as most Linux apps are OSS and thus portable to Windows

True. However, if you work with a large number of open source apps, or even just a lot of Perl modules... Usually these were designed from the start to work under Linux. Yes, the more popular ones compile under both, but sometimes it's a pain, and the less popular ones simply won't compile without extra work.

Also, I just prefer Unix streams/forking/filesystem semantics over Windows. And sure, I use Cygwin/MinGW/etc. a lot, but I'd still take Debian/Ubuntu packages over them any day.

Re:Host OS the one with better drivers (1)

jsailor (255868) | about 7 years ago | (#19676967)

My situation is different, but with the same requirement for a Windows host OS. VirtualBox fills this need quite nicely. The latest release enables the use of VMware disk images, but I haven't tried that. You may wish to try out VirtualBox.

Re:Host OS the one with better drivers (1)

interiot (50685) | about 7 years ago | (#19677607)

I'd prefer to be able to dual-boot directly into Windows or Linux (for when I want the fastest performance in Linux, and give it 100% of the RAM), and also be able to run that Linux installation inside of Windows. However, this requires the VM to support booting off a separate partition, and apparently VirtualBox doesn't support that [virtualbox.org] . (yes, booting the same Linux setup under two very different sets of "hardware" has its challenges [vmware.com] , but it is possible [wikia.com] )

Fundamental performance issues (1)

Mostly a lurker (634878) | about 7 years ago | (#19676063)

Full virtualization, as used in Xen, VMware and VirtualBox, has performance issues that are not yet well understood, but thought to revolve around dramatically increased L2 cache misses. I am not aware that any changes are in the works to fully resolve this.

Operating system virtualization, as used for instance in OpenVZ has far better performance characteristics. This is the way to go at the moment for efficient and low cost data center support of Linux. The problem is that all virtual environments must be using the same kernel, which makes it less useful for software testing.

Re:Fundamental performance issues (1)

Courageous (228506) | about 7 years ago | (#19676771)

Full virtualization, as used in Xen, VMware and VirtualBox, has performance issues that are not yet well understood, but thought to revolve around dramatically increased L2 cache misses. I am not aware that any changes are in the works to fully resolve this.

Hmmmm. No, not really.

Performance problems with VMWare are almost universally associated with the added latency of the multiplexing/demultiplexing code that needs to be run to talk with shared I/O devices. This added latency in turn impacts bandwidth. "L2 cache misses" refers to CPU overhead, of which there is little to speak of in any of the above technologies (5% with VMWare, practically zero with Xen). CPU should be of no concern to you with any virtualization technology that I know of.

I've validated this time and time again with different benchmarks from SPEC (not just the CPU benches, but NFS and so forth, as well as OSDB, basic simultaneous FTP tests, and so on).

C//

Using it... (4, Interesting)

dmayle (200765) | about 7 years ago | (#19676087)

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:Using it... (1)

cheshire_cqx (175259) | about 7 years ago | (#19677495)

I have a VPS ("slice") at Slichehost [slicehost.com] and it's the best thing since... well, you know.

Seriously, it may not be right for all applications, and things like Solaris' zones/containers are quite awesome (much more control over IO, fair share scheduling, etc.), I have one of those too at Joyent, but (like many things Linux) it seems to work, be fast, and get the job done at a great value.

I have seen people complain when they have an app that's IO bound and there's another slice with heavy IO needs--looks like IO contention isn't really managed by the hypervisor--but that's pretty rare.

Besides performance at a great price, you also get the benefits dmayle talks about: easy deployment (you get a choice of prebuilt distros to install), and backups/spanshots (both create and restore) are as easy as clicking a button in the control panel. You can also upsize or downsize your slice from the control panel, and be back online in minutes. Try that with a dedicated server!

desperado... (1)

fattmatt (1042156) | about 7 years ago | (#19676105)

what is more desperate is the people that think these highly specialized OSS apps that are not competitive in terms of features/support are going gain any traction in the market place. ha.

The Problem With Xen (5, Funny)

Aeonite (263338) | about 7 years ago | (#19676177)

Is that Gordon Freeman ruined it.

Xen "Just Works" (I know. I use it every day) (3, Informative)

eno2001 (527078) | about 7 years ago | (#19676207)

Not only that, but I've been running it in a production environment for about a year and I'm about to deploy a HUGE set of servers as VMs using it. Xen beats VMware in one arena: price. If you use the open source version (which I'm doing) it's free. Only VMWare's ESX can compare to Xen. And unlike some people here have been saying, you DON'T need a special processor for Xen unless you plan to virtualize Windows. In my environment, I'm only virtualizing Linux, so I can use regular x86 CPUs dating back to 1998 for Xen. The only exception is the deployment of Zimbra I'm going to do. It requires Redhat Enterprise Linux 4 and NPTL, so I can't run it paravirtualized, it must run HVM which requires the special processors. However, who today isn't getting new hardware with HVM support?

Currently my two Xen servers here at work serve out about four VMs (all paravirtualized on older hardware) for critical and I/O intensive tasks like proxy servers for nearly 1000 machines, or the firewall syslog server for a dual T3 link with about 5000 users behind it sucking the bandwidth dry. So you can't claim it doesn't perform either. Now, if you want point and click administration and an easy set up, then yeah, Xen is behind the times. But performance wise it's leaps and bounds above VMWare. Trust me, I was a VMWare fan before you were in virtualization diapers. And I still am for some applications. But for places where I need something to be cost effective AND give me the features of VMWare ESX, Xen is the ONLY answer.

Re:Xen "Just Works" (I know. I use it every day) (0)

Anonymous Coward | about 7 years ago | (#19676455)

Currently my two Xen servers here at work serve out about four VMs

So how many really? Can't you tell?

Re:Xen "Just Works" (I know. I use it every day) (4, Informative)

eno2001 (527078) | about 7 years ago | (#19676753)

It depends on what I'm doing. If you weren't trying to be cute, I'd say you were trolling. In reality, it's very common practice to use LVM to clone a filesystem, make some changes to the various files that set IP and hostname as well as other unique host settings and bring up alternate "Test" VMs on a Xen box. So some days I might be running three VMs other days eight or ten. It all depends on what I need to do.

As an aside, I forgot to mention that there are NO other products other than VMWare ESX that offer "live migration" of a running VM from one hardware host to another. That's right... you can take a VM that is running with many users actively using it and move it from one physical box to another with only a few milliseconds down time. The users NEVER notice. The free VMWare server can't do that. Micrsoft's Virtual Server can't do that until they have a hypervisor. And there really isn't anything else that can.

Re:Xen "Just Works" (I know. I use it every day) (2, Insightful)

Courageous (228506) | about 7 years ago | (#19676825)

The free VMWare server can't do that. Micrsoft's Virtual Server can't do that until they have a hypervisor. And there really isn't anything else that can.

Well you can try to do that with Xen if you want, but you might be sorry. :) But I suspect you knew that.

Hopefully the Summer release remedies this situation.

C//

Re:Xen "Just Works" (I know. I use it every day) (4, Informative)

div_2n (525075) | about 7 years ago | (#19676707)

The only exception is the deployment of Zimbra I'm going to do. It requires Redhat Enterprise Linux 4 and NPTL

Last I checked, Zimbra runs on Ubuntu 6 [zimbra.com] just fine.

Re:Xen "Just Works" (I know. I use it every day) (1)

tji (74570) | about 7 years ago | (#19677141)

"Just Works" is overstating it quite a bit. Based on my experience, and looking at the other comments here, it's more like Xen "mostly works, after a great deal of learning, googling, and experimenting". Maybe once you've ramped up on it it works well. But, saying it "Just Works" is clearly not the case.

The Xen experience has improved a lot. In Fedora 7, I just had to select the Xen kernel+apps for a package install, and the Xen infrastructure was pretty easily installed. But, getting client VMs running, figuring out the command-line tools and their parameters, and working around quirks too a good deal of effort.

Lies, all lies (3, Informative)

C_Kode (102755) | about 7 years ago | (#19676211)

Another question hanging over Xen performance concerns the availability of paravirtualized drivers for Windows.

This isn't true completely. The problem is you cannot get these drivers by downloading the OpenSource Xen. You MUST buy the XenSource version. If you run Windows on the *complete* open source version, your network throughput is going to suck like you would not believe. You have to use the XenSource version to get the paravirtualized drivers that bring the network performance closer to what it should be. Virtual Iron has a set of drivers also. (which I believe are better than Xen's, but don't hold me to that)

I found a lot of great insight about virtualizing from Xen to VMWare to Virtual Iron and others on this site. http://ian.blenke.com/xen [blenke.com]

Xen is ok (1)

jshriverWVU (810740) | about 7 years ago | (#19676275)

I've tried both and VMWare is just better. I respect Linux/GPL and the OSS movement, though the main reason I use linux is not just those reasons it's because IT WORKS. So when it comes down to Xen or VMware I use vmware because it works better.

Xen is FOSS so there is potential for them to catch up and with the nature of FOSS new ideas can be tossed in easier. So when that day comes I'll gladly switch over, it's just not there yet.

Guaranteed Results (4, Informative)

catdevnull (531283) | about 7 years ago | (#19676421)

If you want to get a colorful thread of comments started on slashdot, there are 3 ways to do it with guaranteed results:

1) Say something bad about linux (or about Apple).

2) Say something good about Microsoft (or about Apple).

3) Throw a grenade in the room about Open Source software like this:

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.

I'm not making any value judgements here--I'm just amused.

Xen and OS X question (1)

Nimey (114278) | about 7 years ago | (#19676535)

I'm getting a Macbook soon, and I want to play around with virtual machines on it.

Is it possible to install e.g. Debian as my host OS, apt-get install xen, and then install Mac OS X inside a Xen virtual machine? This computer has a C2D processor, which supports the Intel VT instructions. I'll also do the same with Windows XP and Vista, and Ubuntu.

If it will work, how well? Will it be a transparent install so that X can directly access the 3D acceleration hardware?

Thanks.

Re:Xen and OS X question (0)

Anonymous Coward | about 7 years ago | (#19676835)

You had better take a close look at Apple's license. It prohibits running OSX on other than Apple hardware. OSX checks before starting. There are accounts on the net about modified versions (which disable the check) running on recent x86 hardware so there are no real technical reasons you can't do it. It's just that the licensing prohibits it.

Re:Xen and OS X question (1)

Nimey (114278) | about 7 years ago | (#19677323)

What the hell does that have to do with it? It's a *Macbook*, which is by definition Apple hardware.

Re:Xen and OS X question (1)

SanityInAnarchy (655584) | about 7 years ago | (#19677499)

It's also a virtual machine.

I remember, when I first got WinXP on this machine (free, courtesy of my school), I installed it in Qemu. I then tried to install it directly on the hardware, and it insisted that it was a different computer, and I would have to re-activate it. I called MS, and I had to explain to a woman with a thick Indian accent that it was the same machine. (She didn't have a clue about virtualization.)

The problem is, legally, is a VM the same computer, or a different one? It's one of those tricky philosophical questions...

In any case, the Vista license answers this specifically -- if I recall, only Ultimate may legally be installed under VMs, and a VM is clearly enough defined, I think, that you can't pretend that a Transmeta processor or the Intel/AMD microcode is at all like a VM.

Re:Xen and OS X question (1)

Nimey (114278) | about 7 years ago | (#19678373)

OK, fine, but let's ignore the legal question (since it'll be the only copy of OSX running) and go technical.

Will it work?

Currently using Xen... (1)

BJZQ8 (644168) | about 7 years ago | (#19676555)

My company is currently using Xen on something like 40 "virtual machines" on 6 "real machines." Works almost flawlessly. Runs heavily-used multi-gigabyte MySQL databases and Java web apps without complaining. You can move virtual machines between real machines while they're under load, with a 6ms delay. If a developer wants to try something weird, go ahead. If you hose the system, I'll just re-image it and have you going again in 5 minutes. There's nothing wrong with Xen at all, if it's done right. It's ready for the datacenter, because we use it now.

Re:Currently using Xen... (1)

Courageous (228506) | about 7 years ago | (#19676985)

You can move virtual machines between real machines while they're under load, with a 6ms delay.

That's really interesting. See, the authors of Xen say live migration isn't ready and that it's unstable. I have deployments of redhat, suse, and open source xen that prove that with swarm-cloud migration testing (just put all the vms into flight constantly, ping-ponging around to various hypervisors). Meanwhile, Xen Enterprise does not today feature live migration. Why? Did I say that it's not ready, and that the authors say that it's not ready? Xen Enterprise is the author's commercial implementation of Xen. What do they know that you do not?

That live migrations fail, occasionally, for no apparent reason. Most common failure: live migration never ends, get stuck with a zombie on other end. Rarer failure: host operating system crashes, taking all virtual machines with it.

Don't get me wrong. I have high hopes for Xen in the future. But advertising Xen as "data center ready" TODAY is irresponsible. It just isn't ready for anything past judicious and careful early deployment.

C//

6ms??? (1)

pem (1013437) | about 7 years ago | (#19677463)

Umm, assuming zero overhead, even with 10Gb ethernet, you could only move around 7.1 MB in 6 milliseconds.

With Gigabit Ethernet, you can divide that down to well under a megabyte.

While I'm sure your virtual machines are nice toys, they ARE just toys.

Re:6ms??? (1)

msh104 (620136) | about 7 years ago | (#19678197)

naturally he is telling you that there is an added 6ms to the response time on your server WHILE it is transfering.

Xen's Maturity (3, Insightful)

Krondor (306666) | about 7 years ago | (#19676757)

He concludes that the virtualization technology has some maturing to do...

I RTFA and it says very little about the maturity of the actual Xen technology. The article is more a point about several non-related factors;

1.) There is a lack of pretty management interfaces.

True, but these are in the works from Red Hat, Novell, XenSource, and various other ends. Already some of them look pretty promising, but if you are a real admin you don't need them in the first place. There is nothing wrong with using the command line tools to manage your Xen virtual guest environment.

2.) There is a lack of references for companies using Xen.

How does this relate to the viability of the Xen virtualization? Yeah it makes management feel nice and fuzzy that others are using something, but this does not relate to how well the Xen technology performs. I also suspect that like many open source projects, there are many people using it that do not report it. Novell has personally contacted me and my company to ask us to assist in their new paravirtualized Windows drivers initiative and then be a reference for the technology. It seems that at least some companies are moving to address this, at any rate.

3.) There aren't many benchmarks about Xen versus VMWare.

VMWare does not allow benchmarks they do not approve of. It's in that draconian EULA you agreed to by using it.

4.) It's awkward to paravirtualize Windows.

Yes, it is. Novell signed the soul sapping agreement with MS and as such is pushing some paravirtualized drivers for Windows. The article continually talks about woes with Xen on Red Hat. Red Hat didn't sign the agreement and will require some much more intelligent coding to make this happen. It might never happen, so for Windows it's full virtualization with VT (or AMD's equivalent) or bust. Sorry, use SUSE for it or use full virtualization. It's an MS issue not a Xen issue.

5.) MS's new Viridan Virtualization Platform is using paravirtualization as well.

Yep, that should be a testament to the approach versus VMWare. Though it is interesting that VMWare now has a Linux kernel virtualization implementation similar to KVM. It seems VMWare is headed to paravirtualization as well. Obviously Xen did something right.

6.) There is a lot of competition.

True. How again is this relating to Xen as a virtualization technology.

Again, I'm not saying Xen is perfect. It definitely has issues and room to grow. I'm just saying that the article makes little, if any, relevant points to Xen's virtualization technology.

Re:Xen's Maturity (1)

drsmithy (35869) | about 7 years ago | (#19677485)

True, but these are in the works from Red Hat, Novell, XenSource, and various other ends. Already some of them look pretty promising, but if you are a real admin you don't need them in the first place. There is nothing wrong with using the command line tools to manage your Xen virtual guest environment.

It's not just about pretty pictures, it's about usability. For example, Xen is a bitch to setup with any sort of non-trivial networking environment (eg: multiple vlans, bonded interfaces, etc). You frequently have to write your own scripts to make it work in such situations, but this requires a very good - arguably completely unnecessary - understanding of what's going on behind the scenes.

Now, while this might serve to make some people feel like their e-dick is huge, for those of us that actually have to get work done, and have a perspective of a picture bigger than writing some scripts to do the job someone else should have, it's nothing but a pain in the arse and a waste of time. Firstly, because it requires hours(/days/weeks) of research and work to get the initial configuration going, that has to be scheduled with all the others tasks in the pipeline. Secondly, because it makes all those machines "different" in annoying ways from other machines with ostensibly similar configurations, thus (needlessly) increasing sysadmin overhead. Thirdly, because the requisite for in-depth knowledge extends to everyone who might have to play any sort of role in managing the system, meaning your understaffed IT department is less effective.

That's just one example. There are many more (eg: live migration of VMs) where Xen can sort-of, kinda, emulate the features present in something like VMWare ESX, but you have to spend weeks researching and testing the configuration, instead of spending twenty minutes following the step-by-step instructions in the (*gasp*) documentation, then forgetting it ever happened.

I've never understood why some people - OSS unix geeks in particular - consider the quality of software to be inversely related to how easy it is to use. I can only assume it's because they're worried the Priesthood would be threatened if people only realised that a nontrivial proportion of "sysadmins" are little more than helpdesk staff who just happen to know the right incantations.

I'm sure there are many people using Xen in "enterprise" scenarios. We are, but only because the manpower is largely already spent. If I'd known before I started pursuing Xen what I know now, my advice to myself would be the same to my advice to most people looking into enterprise-level virtualisation - get VMWare ESX. You might think it's expensive, but it's almost a certainty you'll spend more money on Xen in wasted manpower trying to get it up to half the functionality and relability. Just give them the money and get on with improving your environment in ways that will boost productivity, rather than pouring manpower into a black hole of effort polishing up someone else's half-finished product.

Re:Xen's Maturity (1)

martyros (588782) | about 7 years ago | (#19678193)

You frequently have to write your own scripts to make it work in such situations, but this requires a very good - arguably completely unnecessary - understanding of what's going on behind the scenes.

You seem to be complaining that the Xen hypervisor doesn't do anything with networking. That's not what a hypervisor is for. Setting up virtual networks is outside the scope of a hypervisor; that's why you need other tools. It would be like complaining 10 years ago that Linux worked fine for process management, but that it was a pain to set up networking, that you needed to edit all kinds of scripts and nonsense. That's got nothing to do with the kernel, but with the lack of supporting tools to make configuration easy. Just like the graphical tools needed to be developed for networking and other configuration for Linux, the tools for management still need to be created for Xen.

VMWare has been developing their management interfaces and infrastructure for 6-7 years now. Don't be surprised that RedHat, XenSource, Virtual Iron, et al don't have parity after less than a year of working on it.

Re:Xen's Maturity (1)

martyros (588782) | about 7 years ago | (#19677603)

There is a lack of pretty management interfaces.

This seems to be one of his main disappointments, in fact -- specifically, that RHEL 5 doesn't have pretty management interfaces. (The only mention of XenSource and Virtual Iron's management interfaces seems to be to re-emphasize that RHEL's GUI is really bad.)

The Xen hypervisor is an engine, not a car. Xen is in some ways similar to where Linux was in the late '90s -- the kernel worked great, but the GUI was way behind. And the fact is that corporate customers need a complete solution, not just a great "engine". The number of cool features of the OSS Xen is really astounding -- but without a convenient way to manage it for mere mortals, it's not that much use to most IT folks. And getting that functionality, along with other functionality that IT folks might need (like say, storage management) into a useful GUI is a very difficult proposition, and not at all related to the virtualization technology itself.

Xen vs. VMware (1)

TheRealFixer (552803) | about 7 years ago | (#19676941)

I'm primarily a VMware VI3 user, but I've been starting to do more with Xen lately. I have to say, Xen is very impressive in what it accomplishes. It's very stable, and has the capability to do some really advanced stuff. That being said, it can be a real pain to get some of those advanced features working. For example, running Xen in CentOS 5, I had a server with two NICs, and I wanted to setup a second bridged interface for the second NIC. It took way more effort than it should have to get that working correctly. In ANY VMware product, that's a task that takes, literally, seconds. Another thing I'm working on is getting VMs to auto-boot in a particular order, and wait on another VM to finish booting before the next one starts. Again, a task that's second nature in VMware, but appears to be difficult to implement in Xen.

In the end, it all boils down to management tools. There are no decent centralized tools to manage a farm of Xen servers right now, let alone manage just one host. Virt-manager is very helpful, but extremely limited. And I've looked into some web-based management applications, but none of them are anywhere close to mature enough to deploy in a data center. Xen is still my choice for free Linux virtualization, but they've got a long way to go to even approach VMware.

Xen Management Apps Are Not Good. (2, Informative)

tji (74570) | about 7 years ago | (#19677001)

I have been trying to use Xen at home to test it out and compare it to VMWare, which I've used at work. Once you manage to get Xen clients working, it's fine. It does a good job of running VMs, and can be used to partition resources on a powerful machine.

But, the main problem is the steep learning curve for getting Xen running in the first place. The (python based) management GUIs included with Fedora or Ubuntu are weak at best (although, slowly improving.. the UI in Fedora 7 does manage to make setup easier than the command-line alternative). The ongoing management / monitoring of VMs is okay, but weak in comparison to VMWare.

There are also a lot of little quirks in Xen. Installing Win2k in a client VM required a lot of searching for how to attach an ISO image to a running VM (it's not a simple GUI operation like in VMWare/Parallels/VirtualPC, it requires a terminal command with unintuitive options, which never worked for me.. I finally dug out my CD and got the physical CD drive to attach to the VM). Windows VMs have an odd issue where the mouse pointer is offset form the actual pointer (it's a known issue, and is helped by turning off mouse acceleration in Windows preferences, but it is still a problem). Installing client VMs can be challenging.. Ubuntu feisty wouldn't install until I set the VM as a Solaris client, and after a few other tweaks it finally installed and worked fairly well.

Most of the Xen problems are solvable, after playing with command-line tools, figuring out poorly documented parameters, and lots of googling. At the end of the day, it's one of those "Xen is free, if your time has no value" type things. VMWare Server is probably a better option if you just want it to work for home/free uses. For commercial use, VMWare ESX Server is the way to go. It has simple VM setup for many client OS's, excellent management of large groups os Hypervisors and virtual machines.

The commercial alternative from XenSource (free to use, but limited to 4 VMs; or less restricted versions for increasing $$) offer a better management UI, but are too restricted for my taste. The management app is much better, but not as good as VMWare.. If I'm going to pay for one, I'll go for the best option.

Summary of article: (1)

Larry_Dillon (20347) | about 7 years ago | (#19677247)

Not enough market share and immature (optional) GUI == Not Ready for Prime Time.

"Oh my. Editable XML configuration files, obscure command line interfaces, grayed out options in the GUI? Thanks, but no thanks. This thing doesn't sound like it's ready for prime time in Data Center USA."

I say if you can't use the command line YOU'RE not ready for "prime time in Data Center USA."

Data Center USA (5, Insightful)

fyoder (857358) | about 7 years ago | (#19677283)

I stopped reading the article with this quote:

Oh my. Editable XML configuration files, obscure command line interfaces, grayed out options in the GUI? Thanks, but no thanks. This thing doesn't sound like it's ready for prime time in Data Center USA.

Are sysadmins at "Data Center USA" morons? "Oh nooo, command line time, I hate that. Oh nooo, my option I want is all grayed out! Help me, help me! Oh I am so sad now."

Deploying vm stuff is not the same as using a word processor. "Data Center USA" is in real trouble if their sysadmins aren't any smarter than regular desktop users.

Xen corrupts data (1)

pseudorand (603231) | about 7 years ago | (#19677305)

I was a big fan of Xen until I found out it was silently corrupting data. I've only duplicated the problem on an older 3ware card, but I was just about to trash the card, drives, etc. when I discovered that I couldn't duplicate the problem when using a non-xen kernel. Now I'm just waiting for pacifica and ivt solutions to mature before I touch virtualization for anything important.

Xen? Didn't we already.... (-1, Redundant)

Anonymous Coward | about 7 years ago | (#19677415)

done that in 1998?
Damn you Gordon Freeman!

Two words: OpenVZ (2, Insightful)

pyite69 (463042) | about 7 years ago | (#19677745)


If you are running the same OS on each VM on a server, OpenVZ is the best.

Performance is great, good control over resources (with the glaring exception of disk IO operations, which they are working on).

Scientology and Mental Health (0)

Anonymous Coward | about 7 years ago | (#19677809)

For a moment there I thought the submitter mean 'Desperately Seeking Xenu'.
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