Re: [Oneiric-Topic] Revisit Xen support
On 5/30/11 8:35 PM, Jorge Armando Medina wrote: > On 03/30/2011 08:27 AM, Chuck Short wrote: >> Hi, >> >> In the past Xen support in Ubuntu as a host has been difficult for a >> variety of reasons most notably no upstream kernel support. Now that >> dom0 should be coming into the vanilla kernel soon. I think its time to >> revisit supporting Xen as a hypervisor as well. >> >> Regards >> chuck >> > Hi there, > > Linus just accepted almost all the xen bits in 2.6.39+, this will allow > Linux to run in Xen as Domain-0 and DomainU fully paravirtulized, more info: > I'd really like to see some more distribution support (especially ubuntu) behind xen. DomU support in natty is already *not so bad* and with a 2.6.40/3.0 kernel in oneiric the dom0 support shouldn't be much of a problem either. Just the hypervisor that's missing... I am using xen 4.1 packages on natty. They still have some rough edges but if you know what you are doing they already work *not so bad* too :) I put the packages online at [1]. They're basically a debian-unstable remake. [1] https://launchpad.net/~dokter/+archive/xen-4.1 > > Best regards. > cheers, Mark -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: [Oneiric-Topic] Revisit Xen support
On 03/30/2011 08:27 AM, Chuck Short wrote: > Hi, > > In the past Xen support in Ubuntu as a host has been difficult for a > variety of reasons most notably no upstream kernel support. Now that > dom0 should be coming into the vanilla kernel soon. I think its time to > revisit supporting Xen as a hypervisor as well. > > Regards > chuck > Hi there, Linus just accepted almost all the xen bits in 2.6.39+, this will allow Linux to run in Xen as Domain-0 and DomainU fully paravirtulized, more info: http://blogs.oracle.com/wim/entry/linux_mainline_contains_all_the? http://www.kernel.org/diff/diffview.cgi?file=/pub/linux/kernel/v2.6/snapshots/patch-2.6.39-git20.bz2 Best regards. -- Jorge Armando Medina Computación Gráfica de México Web: http://www.e-compugraf.com Tel: 55 51 40 72, Ext: 124 Email: jmed...@e-compugraf.com GPG Key: 1024D/28E40632 2007-07-26 GPG Fingerprint: 59E2 0C7C F128 B550 B3A6 D3AF C574 8422 28E4 0632 -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: [Oneiric-Topic] Revisit Xen support
On 04/01/2011 06:05 PM, Raphaël Pinson wrote: > On Sat, Apr 2, 2011 at 1:51 AM, Clint Byrum wrote: >> Excerpts from Chuck Short's message of Wed Mar 30 07:27:50 -0700 2011: >>> Hi, >>> >>> In the past Xen support in Ubuntu as a host has been difficult for a >>> variety of reasons most notably no upstream kernel support. Now that >>> dom0 should be coming into the vanilla kernel soon. I think its time to >>> revisit supporting Xen as a hypervisor as well. >> Just playing devil's advocate here. >> >> Other than people already having familiarity with Xen, what is a >> compelling reason to support it in favor of, or in addition to, KVM? > > Familiarity is a good reason I think, but also industry standards, and > hardware considerations. I think a lot of big companies expect major > distributions such as Ubuntu to provide a proper support for such a > standard as Xen. I know it came as a disappointment for us that using > Lucid as a (production) Xen dom0 was nearly impossible. Also, afair, > KVM requires hardware support. Most recent machines provide it, but > it's not rare to find servers that are too old to use it, and then > you'd rather use Xen for servers than VMWare... That is right, We have customers with big servers with lots of ram using xen for paravirtulized machines, xen is a good product and we have really good performance. By the way, Xen is supported with the OpenStack. Best regards. > > Raphaël > -- Jorge Armando Medina Computación Gráfica de México Web: http://www.e-compugraf.com Tel: 55 51 40 72, Ext: 124 Email: jmed...@e-compugraf.com GPG Key: 1024D/28E40632 2007-07-26 GPG Fingerprint: 59E2 0C7C F128 B550 B3A6 D3AF C574 8422 28E4 0632 signature.asc Description: OpenPGP digital signature -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: [Oneiric-Topic] Revisit Xen support
Am Mo, 4.04.2011, 13:34 schrieb Soren Hansen: > 2011/4/4 Clint Byrum : >> Maybe we should ask though. Adding Xen back in means less resources >> for KVM, so the KVM users' opinions matter quite a bit. > > The very short version: I'm fine with Ubuntu getting Xen support again, > but I don't think it needs to be in main. > I think most people here think the same. Xen do not need to be in main. Xen is only needed if there is a demand for a feature Xen has and KVM not. And most people will agree in everything else you wrote in your mail. I have several KVM and Xen server up and running and I think KVM will be (or is, if you prefer ;-) ) the virtualisation technology for the future. But sometimes an admin needs Xen for various reasons and then they get driven away from Ubuntu for now. Something that is not so good for the wide deployment of Ubuntu server. Michael -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: [Oneiric-Topic] Revisit Xen support
2011/4/4 Clint Byrum : > Maybe we should ask though. Adding Xen back in means less resources > for KVM, so the KVM users' opinions matter quite a bit. The very short version: I'm fine with Ubuntu getting Xen support again, but I don't think it needs to be in main. We chose KVM as our preferred, supported hypervisor a long time ago. We've been telling people for years that it's what they should be using, and lots of great effort has been put into the integration work. The arguments against KVM were mostly about the hardware requirements, but if we could live with that in 2007, I'd be surprised if we couldn't today, since the percentage of server hardware that doesn't work with KVM has severely declined. Any decision will have supporters and opponents, and I firmly believe that making a decision is the right thing to do. I believe there's a lot of value (for everyone involved) in having firm answers to even tough questions. Ubuntu, for instance, is a free operating system. No-one has to ask over and over whether it's still free, because we've been very clear from the beginning that that's how we roll. Similarly, you won't find any closed-source applications on an Ubuntu CD. If you're wanting to distribute closed source applications, don't bother asking if you can put it on one of the Ubuntu CD's. No matter how popular your software is, or how many people vote for it on a mailing list or on Ubuntu Brainstorm, it's not going to happen. We're also not going to switch to the FreeBSD kernel on a whim. Every decision we make defines us, whether it's an additive or subtractive one. Every decision we fail to make, weakens us. When we chose KVM as our preferred hypervisor, it wasn't a decision to use it in Hardy and revisit that decision every release following it (that would have made it almost a non-decision). It wasn't a decision to run this or that benchmark every 6 months, and whichever was in the lead would be the preferred, supported hypervisor that we'd go out and praise, and the rest would be deprecated until 6 months later when the numbers would be slightly different. We made the decision even though KVM was still quite young, and none of the other major distros were shipping it. We made the decision to ship it, support it, stand behind it, and help it grow. Ubuntu's hypervisor was KVM. I happily stand by that decision. I believe KVM's design is superior. KVM immediately benefits from improvements made to the Linux kernel. If power management improves in the Linux kernel, your KVM host's power management improves. If the scheduler improves, KVM benefits. If memory management improves, KVM benefits. KVM is part of the Linux kernel, while Xen has its own kernel. I'm not talking about the dom0, I'm talking about the Xen hypervisor on top of which the dom0 and domU's run. This difference means that many improvements in Linux need to be accommodated for or mimicked in Xen before you get the benefits there[1]. To use KVM, you load a module that turns your regular Linux kernel into a hypervisor. To run Xen, you boot a completely different kernel on top of which you run a dom0. For the most part, you don't see the difference, because distributors have put a lot of work into making this change seamless, but effectively, you're not running Linux anymore as your kernel. Anthony Liguori (one of the KVM and QEmu developers) said it quite well[2]: "The whole situation is somewhat absurd though. It's like if the distributions shipped a NetBSD kernel automatically and switched to using it when you wanted to run a LAMP stack." Linux is a fine hypervisor on its own. It may not be perfect, but I'd prefer we focus on identifying and fixing those issues If someone thinks Xen is sufficiently cool, I'd encourage them to put some effort getting it into shape in Ubuntu. I don't think we should divert any of the existing attention on kvm/libvirt/friends to Xen. I don't think we can afford it. [1]: This page on power management with Xen is a good example: http://wiki.xensource.com/xenwiki/xenpm [2]: http://blog.codemonkey.ws/2008/05/truth-about-kvm-and-xen.html -- Soren Hansen | http://linux2go.dk/ Ubuntu Developer | http://www.ubuntu.com/ OpenStack Developer | http://www.openstack.org/ -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: [Oneiric-Topic] Revisit Xen support
On 4 April 2011 13:08, Michael Zoet wrote: > > Maybe we should ask though. Adding Xen back in means less resources for > > KVM, so the KVM users' opinions matter quite a bit. > > In my opinion asking "is some software better than another software" is > the wrong approach. KVM has advantages over Xen and Xen has advantages > over KVM. It depends on a lot of factors which is an appropriate solution > for a given task. Sometimes KVM wins and sometimes Xen and sometimes > VMware and so on. > Ack. +1 KVM should not degraded in favor of Xen. Never! > At least not in the current state of things. One of the major advatages of KVM is its stimplicity, and the fact it's in streamline Linux. As I understood, as well in Debian as In ubuntu, the problem with Xen was keeping it supported in more recent kernels, and managing the whole thing. What SysAdmins need are options to choose from to fit the best in their > networks. If Xen is available in the vanilla kernel a Xen kernel should be > available. But never in favor of a good KVM support. > When Xen gets vanilla support for Dom0, it definitely could get some renewed attention, and things need to be evaluated again. It is the same for MTAs: we have among postfix exim, sendmail, qmail and a > lot of other MTAs in the package repository. One MTA might work better for > a given situation than the others. -- Met vriendelijke groet, Serge van Ginderachter -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: [Oneiric-Topic] Revisit Xen support
On Mon, 04 Apr 2011 02:40:25 -0700 Clint Byrum wrote: > Excerpts from Soren Hansen's message of Mon Apr 04 01:40:39 -0700 > 2011: > > 2011/4/3 Clint Byrum : > > > Excerpts from Clint Byrum's message of Fri Apr 01 16:51:04 -0700 > > > 2011: > > >> Other than people already having familiarity with Xen, what is a > > >> compelling reason to support it in favor of, or in addition to, > > >> KVM? > > > Not one person has stood up and said that KVM blows Xen away, or > > > is even "better". > > > > Um, no... because you didn't ask. > > > > Fair enough. > > Maybe we should ask though. Adding Xen back in means less resources > for KVM, so the KVM users' opinions matter quite a bit. > I totally disagree with this. Adding Xen back would take little effort to do so. Regards chuck -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: [Oneiric-Topic] Revisit Xen support
On 4 April 2011 12:31, Soren Hansen wrote: > 2011/4/2 Serge van Ginderachter : > > On 2 April 2011 16:58, Clint Byrum wrote: > >> Serge, would you mind elaborating on that? I'm looking for facts. > > > > I tested several virtualisation technologies last year. > > I'm terribly sorry, but this information is practically useless. There > Yes, I very well realise that. I only gave some general concusions to give an idea of what we were looking at. I was only trying to slightly elaborate on the matter as an answer to an earlier question on the list. Unfortunately, the reports of those tests are private and not published, and I'm not allowed to do that (don't ask), so I can't fully disclose them. > are no version numbers, no information about configuration, about > backing stores, disk image formats, cache settings, and very little > about hardware, etc. I can't e.g. tell if your factor 8 drop i > performance on Ubuntu for small writes is due to the virtual disk > being backed by a qcow2 on ext4, for instance, and as such, I can't > use the data (and much less the conclusions) for anything. > Yes, lots of things could be optimised, that's for sure. But the main aim of the tests were primarily about comparing Xen and KVM, and as such, similar setups (LVM backed disks, Virtio/HVM hardware, using the same startup scripts on all platforms, ... ) and pretty much most default settings were used. The VM images were all identical, Debian Lenny with ext3. So, while different settings might not be fully optimized in those tests - at the time we were pretty new with this stuff - we did made several tests which could compare different platforms. And our conclusion to that was that KVM in general was less performant than Xen. That is the only point I wanted to make. Obviously, YMMV. Also note that these conclusions don't stop me from still using Ubuntu+KVM for lots of setups, but more because of ease of use than performance. -- Met vriendelijke groet, Serge van Ginderachter -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: [Oneiric-Topic] Revisit Xen support
Am Mo, 4.04.2011, 11:40 schrieb Clint Byrum: > Excerpts from Soren Hansen's message of Mon Apr 04 01:40:39 -0700 2011: >> 2011/4/3 Clint Byrum : >> > Excerpts from Clint Byrum's message of Fri Apr 01 16:51:04 -0700 2011: >> >> Other than people already having familiarity with Xen, what is a >> >> compelling reason to support it in favor of, or in addition to, KVM? >> > Not one person has stood up and said that KVM blows Xen away, or is >> even >> > "better". >> >> Um, no... because you didn't ask. >> > > Fair enough. > > Maybe we should ask though. Adding Xen back in means less resources for > KVM, so the KVM users' opinions matter quite a bit. > In my opinion asking "is some software better than another software" is the wrong approach. KVM has advantages over Xen and Xen has advantages over KVM. It depends on a lot of factors which is an appropriate solution for a given task. Sometimes KVM wins and sometimes Xen and sometimes VMware and so on. KVM should not degraded in favor of Xen. Never! What SysAdmins need are options to choose from to fit the best in their networks. If Xen is available in the vanilla kernel a Xen kernel should be available. But never in favor of a good KVM support. It is the same for MTAs: we have among postfix exim, sendmail, qmail and a lot of other MTAs in the package repository. One MTA might work better for a given situation than the others. Michael -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: [Oneiric-Topic] Revisit Xen support
2011/4/2 Serge van Ginderachter : > On 2 April 2011 16:58, Clint Byrum wrote: >> Serge, would you mind elaborating on that? I'm looking for facts. > > I tested several virtualisation technologies last year. I'm terribly sorry, but this information is practically useless. There are no version numbers, no information about configuration, about backing stores, disk image formats, cache settings, and very little about hardware, etc. I can't e.g. tell if your factor 8 drop i performance on Ubuntu for small writes is due to the virtual disk being backed by a qcow2 on ext4, for instance, and as such, I can't use the data (and much less the conclusions) for anything. -- Soren Hansen | http://linux2go.dk/ Ubuntu Developer | http://www.ubuntu.com/ OpenStack Developer | http://www.openstack.org/ -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: [Oneiric-Topic] Revisit Xen support
Excerpts from Soren Hansen's message of Mon Apr 04 01:40:39 -0700 2011: > 2011/4/3 Clint Byrum : > > Excerpts from Clint Byrum's message of Fri Apr 01 16:51:04 -0700 2011: > >> Other than people already having familiarity with Xen, what is a > >> compelling reason to support it in favor of, or in addition to, KVM? > > Not one person has stood up and said that KVM blows Xen away, or is even > > "better". > > Um, no... because you didn't ask. > Fair enough. Maybe we should ask though. Adding Xen back in means less resources for KVM, so the KVM users' opinions matter quite a bit. -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: [Oneiric-Topic] Revisit Xen support
2011/4/3 Clint Byrum : > Excerpts from Clint Byrum's message of Fri Apr 01 16:51:04 -0700 2011: >> Other than people already having familiarity with Xen, what is a >> compelling reason to support it in favor of, or in addition to, KVM? > Not one person has stood up and said that KVM blows Xen away, or is even > "better". Um, no... because you didn't ask. -- Soren Hansen | http://linux2go.dk/ Ubuntu Developer | http://www.ubuntu.com/ OpenStack Developer | http://www.openstack.org/ -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: [Oneiric-Topic] Revisit Xen support
Quoting Serge van Ginderachter (se...@vanginderachter.be): > On 2 April 2011 16:58, Clint Byrum wrote: > Some general conclusions were: > > * VMWare ESXi was the clear winner, > * Xen on Debian Lenny was a close second, and the winner amongst Open > Source solutions. > * Xen performance is way better than KVM, especially when looking at disk > access > * Xen performs in a more stable and predictable way, whilst KVM seemed > to perform more at random (which confirms Iustin's observations, ) > * CentOS (5.4) performed remarkably well for being older sofwtare > versions (KVM, Xen, Linux kernel) > * performance on Ubuntu was really bad. The then recent Ubuntu Lucid > was far worse than CentOS 5.5 (both KVM) On the one hand, you can't make claims like this without giving very detailed info on the storage configuration. On the other hand, kvm (and libvirt) tend to make changes which impact how you need to tune things to get best performance. Which is not really acceptable in a real enterprise deployment. We've gotten complaints before - valid IMHO - about 'undocumented changes' like that. This is IMO a strong consideration for considering re-enabling xen. It also may deserve a UDS topic on whethere there is something we can do. Perhaps we can spend a week around alpha-3 time doing performance tests of various configurations. Perhaps we can query the community for what they consider current best practices, and document those at release time. Perhaps query, then do our week of performance tests to validate, then document. -serge signature.asc Description: Digital signature -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: [Oneiric-Topic] Revisit Xen support
Excerpts from Clint Byrum's message of Fri Apr 01 16:51:04 -0700 2011: > Excerpts from Chuck Short's message of Wed Mar 30 07:27:50 -0700 2011: > > Hi, > > > > In the past Xen support in Ubuntu as a host has been difficult for a > > variety of reasons most notably no upstream kernel support. Now that > > dom0 should be coming into the vanilla kernel soon. I think its time to > > revisit supporting Xen as a hypervisor as well. > > Just playing devil's advocate here. > > Other than people already having familiarity with Xen, what is a > compelling reason to support it in favor of, or in addition to, KVM? > Really awesome feedback guys, and thanks for putting up with my "tire kicking" on this idea. So what I'm reading is that KVM should be good once hardware catches up with it. Xen takes advantage of older hardware more effectively, and may also have a better I/O system. Not one person has stood up and said that KVM blows Xen away, or is even "better". I have very little operational experience with either.. having had my website and IMAP server on a Xen domU running CentOS 5 for a few years, I can say that it is "fine" for the lightweight work of a wordpress blog and courier-imap. So, with all of that said, and xen dom0 support coming to the vanilla kernel, it sounds like a slam dunk for Ubuntu to raise xen to first class status. -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: [Oneiric-Topic] Revisit Xen support
On 2 April 2011 18:47, Chuck Short wrote: > > I feel like there is a lot of anecdotal evidence, but we shouldn't > > make our decisions just because somebody says KVM can't do this or > > Xen can do that. > I fully agree with that. Whilst I argument that Xen is definitely more performant than KVM, I'm mostly using KVM instead of Xen. So I never said KVM was not good, definitley not. Ubuntu needs to support both technologies, especially when Xen gets vanilla dom0 support. -- Met vriendelijke groet, Serge van Ginderachter -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: [Oneiric-Topic] Revisit Xen support
On Sat, 02 Apr 2011 08:03:11 -0700 Clint Byrum wrote: > Excerpts from Michael Zoet's message of Sat Apr 02 01:20:36 -0700 > 2011: > > > > -BEGIN PGP SIGNED MESSAGE- > > Hash: SHA1 > > > > Am 02.04.2011 02:05, schrieb Raphaël Pinson: > > > On Sat, Apr 2, 2011 at 1:51 AM, Clint Byrum > > > wrote: > > >> Excerpts from Chuck Short's message of Wed Mar 30 07:27:50 -0700 > > >> 2011: > > >> > > >> Just playing devil's advocate here. > > >> > > >> Other than people already having familiarity with Xen, what is a > > >> compelling reason to support it in favor of, or in addition to, > > >> KVM? > > > > > > > > > Familiarity is a good reason I think, but also industry > > > standards, and hardware considerations. I think a lot of big > > > companies expect major distributions such as Ubuntu to provide a > > > proper support for such a standard as Xen. I know it came as a > > > disappointment for us that using Lucid as a (production) Xen dom0 > > > was nearly impossible. Also, afair, KVM requires hardware > > > support. Most recent machines provide it, but it's not rare to > > > find servers that are too old to use it, and then you'd rather > > > use Xen for servers than VMWare... > > > > > > > I agree with that! Really big companies choose the things they know. > > And if they have to switch the distro they do it. > > > > Noted. It sounds like Xen has a lot of inertia. > > > Another advantage for Xen: it is more mature and easier to setup (at > > least for me because I have only one configuration file I can change > > with vim). Much more documentation around that works. You have much > > more network options. And you can easily assign a hardware NIC to a > > VM with Xen. With KVM this does not work on every hardware... (Now > > I have 2 15.000,- ? servers where I can not do the things with KVM > > I could easily do with Xen. This was a pitty experience...) > > > > I feel like a broken record, but could you provide us with some facts > to back up these claims? Bug reports, manual pages, etc. > > > I feel like there is a lot of anecdotal evidence, but we shouldn't > make our decisions just because somebody says KVM can't do this or > Xen can do that. > http://iopscience.iop.org/1742-6596/.../1742-6596_219_4_042005.pdf Again Im not saying we should drop KVM in favor of XEN. if it something our users want then. We should at least have a better solution in Ubuntu than what we have now. chuck -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: [Oneiric-Topic] Revisit Xen support
On 2 April 2011 16:58, Clint Byrum wrote: > > > Other than people already having familiarity with Xen, what is a > > > compelling reason to support it in favor of, or in addition to, KVM? > > > Performance. > > Serge, would you mind elaborating on that? I'm looking for facts. > I tested several virtualisation technologies last year. I told my conclusions earlier on another list, but I'll copy paste them here for easier follow-up: https://groups.google.com/d/msg/ganeti/JKejnQkAhgI/OdFBbww3K_cJ About a small year ago, I have been conducting some various tests on comparing different virtualisation technologies on different platforms. * tested VMWare ESXi, Xen on Debian and CentOS and KVM on Ubuntu and CentOS * these tests have nothing to do with Ganeti, nor was there a test with DRBD, * on Xen and KVM I tested using HVM/Virtio - not so on VMWare * made different tests, stressing CPU, disk, memory and network on 1 till 10 concurrent vm's. * client vm machines were all Debian Lenny Some general conclusions were: * VMWare ESXi was the clear winner, * Xen on Debian Lenny was a close second, and the winner amongst Open Source solutions. * Xen performance is way better than KVM, especially when looking at disk access * Xen performs in a more stable and predictable way, whilst KVM seemed to perform more at random (which confirms Iustin's observations, ) * CentOS (5.4) performed remarkably well for being older sofwtare versions (KVM, Xen, Linux kernel) * performance on Ubuntu was really bad. The then recent Ubuntu Lucid was far worse than CentOS 5.5 (both KVM) * Disk speed on bare metal was 80MB/s * on vm, those dropped to 40-20MB/s depending on the platform end thenumber of concurrent access (= number of tested vm's) Also, testing latency (lots of small writes): time dd if=/dev/zero of=/dev/vda5 bs=512 count=10 oflag=direct * 4.6 MB/s on bare metal * 728 KB/s on vm Ubuntu + KVM * on vm Debian Lenny + Xen:don't have the number anymore but noted a performance drop of only 20% It really struck me how Ubuntu's performance was really bad, even when comparing the then recent Lucid to a Red Hat backported kernel (still 2.6.18) Of course, lots of things have evolved since then, but when looking at the major distro's, to update conclusions, one should look at Debian Squeeze and Red Hat 6. At least for Ubuntu, no things have changed if you only consider Ubuntu LTS as a contender (which is how I look at it at least). -- Met vriendelijke groet, Serge van Ginderachter -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: [Oneiric-Topic] Revisit Xen support
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Am 02.04.2011 17:03, schrieb Clint Byrum: ... >> Another advantage for Xen: it is more mature and easier to setup (at >> least for me because I have only one configuration file I can change >> with vim). Much more documentation around that works. You have much >> more network options. And you can easily assign a hardware NIC to a VM >> with Xen. With KVM this does not work on every hardware... (Now I have >> 2 15.000,- ? servers where I can not do the things with KVM I could >> easily do with Xen. This was a pitty experience...) >> > > I feel like a broken record, but could you provide us with some facts > to back up these claims? Bug reports, manual pages, etc. https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/741706 I am into further investigations here. But the two servers are already in production use, so it is hard to test and get deeper into it. For now I help myself with all kinds of proxying. But for real virtualized gateways / routers there is no good solution for me now with KVM. > > > I feel like there is a lot of anecdotal evidence, but we shouldn't make > our decisions just because somebody says KVM can't do this or Xen can > do that. > That's right but Unix/Linux SysAdmins need options to choose from! If Xen integration is easily done then Ubuntu Server should provide these option. If not SysAdmins are forced to use other distros like SLES or CentOS. That's the trueth in many datacenters. By the way: KVM has lot of advatages, too. As always you have to choose which one fits best ;-). Michael -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.10 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAk2XQ9kACgkQBvfZ5167qr8E1gCfewctSDhA3iapO3RBpFaHcokl 2zgAoKaJIVEEa3p4DTj52hDGxQBg2PBd =0RVX -END PGP SIGNATURE- -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: [Oneiric-Topic] Revisit Xen support
On Sat, Apr 2, 2011 at 5:03 PM, Clint Byrum wrote: > Noted. It sounds like Xen has a lot of inertia. I'd say big companies have a lot of inertia. Once they have chosen to invest in a technology, be it Xen or KVM, they build systems on this technology for years, hire experts (and get their employees to become experts), and they're not willing to reconsider their position a few months after (or even years) after just because the trend has changed. Xen was the state-of-the-art not so long ago, and it's already taken these big companies long enough to use it. KVM is the medium-to-long term future for many still. > I feel like there is a lot of anecdotal evidence, but we shouldn't make > our decisions just because somebody says KVM can't do this or Xen can > do that. I think many would agree that with current hardware and a brand new DC, it's generally a better idea to invest in KVM than Xen. But if we want Ubuntu to be an enterprise class OS for servers, that means we need to provide the tools for people to be conservative if they want to, and not to have to rethink the technology they've been successfully using for years. So, encouring the use of KVM, I'm all for it ; supporting the people who still need to use Xen and would like to do so with Ubuntu, that's also a major point if you want Ubuntu to be a reference in DCs. Nowadays, who would use inetd to implement a network service if they have xinetd at hand? I guess not many people. But we're not going to remove inetd from Ubuntu, because a lot of old services still use it and it's a standard per se, whether we use it for internal Ubuntu development or not. Raphaël -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: [Oneiric-Topic] Revisit Xen support
Excerpts from Michael Zoet's message of Sat Apr 02 01:20:36 -0700 2011: > > -BEGIN PGP SIGNED MESSAGE- > Hash: SHA1 > > Am 02.04.2011 02:05, schrieb Raphaël Pinson: > > On Sat, Apr 2, 2011 at 1:51 AM, Clint Byrum wrote: > >> Excerpts from Chuck Short's message of Wed Mar 30 07:27:50 -0700 2011: > >> > >> Just playing devil's advocate here. > >> > >> Other than people already having familiarity with Xen, what is a > >> compelling reason to support it in favor of, or in addition to, KVM? > > > > > > Familiarity is a good reason I think, but also industry standards, and > > hardware considerations. I think a lot of big companies expect major > > distributions such as Ubuntu to provide a proper support for such a > > standard as Xen. I know it came as a disappointment for us that using > > Lucid as a (production) Xen dom0 was nearly impossible. Also, afair, > > KVM requires hardware support. Most recent machines provide it, but > > it's not rare to find servers that are too old to use it, and then > > you'd rather use Xen for servers than VMWare... > > > > I agree with that! Really big companies choose the things they know. > And if they have to switch the distro they do it. > Noted. It sounds like Xen has a lot of inertia. > Another advantage for Xen: it is more mature and easier to setup (at > least for me because I have only one configuration file I can change > with vim). Much more documentation around that works. You have much > more network options. And you can easily assign a hardware NIC to a VM > with Xen. With KVM this does not work on every hardware... (Now I have > 2 15.000,- ? servers where I can not do the things with KVM I could > easily do with Xen. This was a pitty experience...) > I feel like a broken record, but could you provide us with some facts to back up these claims? Bug reports, manual pages, etc. I feel like there is a lot of anecdotal evidence, but we shouldn't make our decisions just because somebody says KVM can't do this or Xen can do that. -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: [Oneiric-Topic] Revisit Xen support
Excerpts from Serge van Ginderachter's message of Sat Apr 02 02:17:29 -0700 2011: > On 2 April 2011 01:51, Clint Byrum wrote: > > > Other than people already having familiarity with Xen, what is a > > compelling reason to support it in favor of, or in addition to, KVM? > > > > > Performance. > Serge, would you mind elaborating on that? I'm looking for facts. -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: [Oneiric-Topic] Revisit Xen support
On 2 April 2011 01:51, Clint Byrum wrote: > Other than people already having familiarity with Xen, what is a > compelling reason to support it in favor of, or in addition to, KVM? > Performance. -- Met vriendelijke groet, Serge van Ginderachter -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: [Oneiric-Topic] Revisit Xen support
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Am 02.04.2011 02:05, schrieb Raphaël Pinson: > On Sat, Apr 2, 2011 at 1:51 AM, Clint Byrum wrote: >> Excerpts from Chuck Short's message of Wed Mar 30 07:27:50 -0700 2011: >> >> Just playing devil's advocate here. >> >> Other than people already having familiarity with Xen, what is a >> compelling reason to support it in favor of, or in addition to, KVM? > > > Familiarity is a good reason I think, but also industry standards, and > hardware considerations. I think a lot of big companies expect major > distributions such as Ubuntu to provide a proper support for such a > standard as Xen. I know it came as a disappointment for us that using > Lucid as a (production) Xen dom0 was nearly impossible. Also, afair, > KVM requires hardware support. Most recent machines provide it, but > it's not rare to find servers that are too old to use it, and then > you'd rather use Xen for servers than VMWare... > I agree with that! Really big companies choose the things they know. And if they have to switch the distro they do it. Another advantage for Xen: it is more mature and easier to setup (at least for me because I have only one configuration file I can change with vim). Much more documentation around that works. You have much more network options. And you can easily assign a hardware NIC to a VM with Xen. With KVM this does not work on every hardware... (Now I have 2 15.000,- ? servers where I can not do the things with KVM I could easily do with Xen. This was a pitty experience...) Michael -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.10 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAk2W3E8ACgkQBvfZ5167qr84eACfSCUbvBfbvlYQPTOeZ0pqxgJE QfkAmwQuRa+u544lWrxruLWj8IIOiQX3 =sqYU -END PGP SIGNATURE- -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: [Oneiric-Topic] Revisit Xen support
On Sat, Apr 2, 2011 at 1:51 AM, Clint Byrum wrote: > Excerpts from Chuck Short's message of Wed Mar 30 07:27:50 -0700 2011: >> Hi, >> >> In the past Xen support in Ubuntu as a host has been difficult for a >> variety of reasons most notably no upstream kernel support. Now that >> dom0 should be coming into the vanilla kernel soon. I think its time to >> revisit supporting Xen as a hypervisor as well. > > Just playing devil's advocate here. > > Other than people already having familiarity with Xen, what is a > compelling reason to support it in favor of, or in addition to, KVM? Familiarity is a good reason I think, but also industry standards, and hardware considerations. I think a lot of big companies expect major distributions such as Ubuntu to provide a proper support for such a standard as Xen. I know it came as a disappointment for us that using Lucid as a (production) Xen dom0 was nearly impossible. Also, afair, KVM requires hardware support. Most recent machines provide it, but it's not rare to find servers that are too old to use it, and then you'd rather use Xen for servers than VMWare... Raphaël -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: [Oneiric-Topic] Revisit Xen support
Excerpts from Chuck Short's message of Wed Mar 30 07:27:50 -0700 2011: > Hi, > > In the past Xen support in Ubuntu as a host has been difficult for a > variety of reasons most notably no upstream kernel support. Now that > dom0 should be coming into the vanilla kernel soon. I think its time to > revisit supporting Xen as a hypervisor as well. Just playing devil's advocate here. Other than people already having familiarity with Xen, what is a compelling reason to support it in favor of, or in addition to, KVM? -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: [Oneiric-Topic] Revisit Xen support
On Wed, Mar 30, 2011 at 4:27 PM, Chuck Short wrote: > Hi, > > In the past Xen support in Ubuntu as a host has been difficult for a > variety of reasons most notably no upstream kernel support. Now that > dom0 should be coming into the vanilla kernel soon. I think its time to > revisit supporting Xen as a hypervisor as well. This is great news. Where I work, we had considered using Lucid as a dom0 but it was just a mess, and we did not want to consider KVM, so we ended up using CentOS dom0 (and even then, we got stuck with 2.6.18 kernels until recently, which was a big issue for Lucid and up domUs). I'll all for an officiel support for Ubuntu dom0, especially if it's vanilla! Raphaël -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: [Oneiric-Topic] Revisit Xen support
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 03/30/2011 08:35 AM, Etienne Goyer wrote: > On 11-03-30 10:27 AM, Chuck Short wrote: >> Hi, >> >> In the past Xen support in Ubuntu as a host has been difficult for a >> variety of reasons most notably no upstream kernel support. Now that >> dom0 should be coming into the vanilla kernel soon. I think its time to >> revisit supporting Xen as a hypervisor as well. > > I do not have much to contribute to the technical discussion around Xen > dom0. All I can say is that, in my work with corporate end-users, it's > a FAQ; seems like Xen is entrenched in a lot of organisations. > Maintaining and supporting a dom0 kernel would make the life of these > organisations much easier, and even open new opportunities for Ubuntu in > the enterprises. > > I agree, there is a lot of organizations that prefere Xen over KVM, much of them are stuck with xen 3.2 in hardy, or a manual setup compiling from sources. My vote for xen revist - -- Compugraf -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.10 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAk2WVykACgkQxXSEIijkBjK08wCfYgTi1ym3R+lkXcd8sUgZphqb cD4Anj7RL62D9K+pq6XinJzjXkA3vm1o =wYyh -END PGP SIGNATURE- -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: [Oneiric-Topic] Revisit Xen support
+1 for xen dom0 support! On Wed, Mar 30, 2011 at 10:27 AM, Chuck Short wrote: > Hi, > > In the past Xen support in Ubuntu as a host has been difficult for a > variety of reasons most notably no upstream kernel support. Now that > dom0 should be coming into the vanilla kernel soon. I think its time to > revisit supporting Xen as a hypervisor as well. > > Regards > chuck > > -- > ubuntu-server mailing list > ubuntu-server@lists.ubuntu.com > https://lists.ubuntu.com/mailman/listinfo/ubuntu-server > More info: https://wiki.ubuntu.com/ServerTeam > -- Please avoid sending me Word or PowerPoint attachments. See http://www.gnu.org/philosophy/no-word-attachments.html -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: [Oneiric-Topic] Revisit Xen support
On 11-03-30 10:27 AM, Chuck Short wrote: > Hi, > > In the past Xen support in Ubuntu as a host has been difficult for a > variety of reasons most notably no upstream kernel support. Now that > dom0 should be coming into the vanilla kernel soon. I think its time to > revisit supporting Xen as a hypervisor as well. I do not have much to contribute to the technical discussion around Xen dom0. All I can say is that, in my work with corporate end-users, it's a FAQ; seems like Xen is entrenched in a lot of organisations. Maintaining and supporting a dom0 kernel would make the life of these organisations much easier, and even open new opportunities for Ubuntu in the enterprises. -- Etienne Goyer Technical Account Manager - Canonical Ltd Ubuntu Certified Instructor -LPIC-3 ~= Ubuntu: Linux for Human Beings =~ -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
