Hello all needed your views and review on which one is better on RHEL xen or kvm ? _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Wed, Apr 21, 2010 at 10:20 AM, Arpan Jindal <jindalarpan@gmail.com>wrote:> Hello all > > needed your views and review on which one is better on RHEL xen or kvm ? > >KVM is easier because Redhat''s focus is on it and it''s a simpler system to use. I only use it for prototyping and development work and Xen for large deployments. Xen''s learning curve is straight up but for Linux on Linux virtualizing still has quite a bit of lead over KVM for performance in most categories (except for VM to VM network performance). Like many I''m taking my hardware to the limit so I need all I can get. I''m moving to Xen Cloud Platform soon which is a custom RHEL/CentOS based distro with the Xen software and a much newer kernel. I will be a lot more interested in KVM when Spice is up and working which I think is happening in RHEL 5.5. I know you didn''t ask about KVM anywhere else but Ubuntu Cloud Server uses KVM and is very attractive. Grant McWilliams _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
That depends on who you ask and what you''re doing. You''re asking that question on a Xen mailing list, so I''d venture a guest that most of us here (yes, us, as in, me too) are going to feel that Xen is a better choice. What are you trying to accomplish in terms of virutalization? -Nick>>> On 2010/04/21 at 11:20, Arpan Jindal <jindalarpan@gmail.com> wrote: > Hello all > > needed your views and review on which one is better on RHEL xen or kvm ?-------- This e-mail may contain confidential and privileged material for the sole use of the intended recipient. If this email is not intended for you, or you are not responsible for the delivery of this message to the intended recipient, please note that this message may contain SEAKR Engineering (SEAKR) Privileged/Proprietary Information. In such a case, you are strictly prohibited from downloading, photocopying, distributing or otherwise using this message, its contents or attachments in any way. If you have received this message in error, please notify us immediately by replying to this e-mail and delete the message from your mailbox. Information contained in this message that does not relate to the business of SEAKR is neither endorsed by nor attributable to SEAKR. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
I have been using Xen on RHEL from last 3+ years but today i was seeing some one using KVM on RHEL and, that lead me to ask all which one is better and how . so basically i mean to ask what features xen does have over KVM if any or both same ? On Thu, Apr 22, 2010 at 2:20 AM, Nick Couchman <Nick.Couchman@seakr.com>wrote:> That depends on who you ask and what you''re doing. You''re asking that > question on a Xen mailing list, so I''d venture a guest that most of us here > (yes, us, as in, me too) are going to feel that Xen is a better choice. > > What are you trying to accomplish in terms of virutalization? > > -Nick > > >>> On 2010/04/21 at 11:20, Arpan Jindal <jindalarpan@gmail.com> wrote: > > Hello all > > > > needed your views and review on which one is better on RHEL xen or kvm ? > > > > > -------- > This e-mail may contain confidential and privileged material for the sole > use of the intended recipient. If this email is not intended for you, or > you are not responsible for the delivery of this message to the intended > recipient, please note that this message may contain SEAKR Engineering > (SEAKR) Privileged/Proprietary Information. In such a case, you are > strictly prohibited from downloading, photocopying, distributing or > otherwise using this message, its contents or attachments in any way. If > you have received this message in error, please notify us immediately by > replying to this e-mail and delete the message from your mailbox. > Information contained in this message that does not relate to the business > of SEAKR is neither endorsed by nor attributable to SEAKR. >_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
The two are very different systems. Xen is a hypervisor - that is, Xen is a kernel that actually runs on the hardware, and then loads domains on top of that. dom0, the privileged domain, helps Xen manage resource allocation to the different unprivileged domains (domUs), but dom0 is running on top of Xen the same way that the domUs run on top of Xen. KVM is a Linux kernel virtualization infrastructure, and runs inside the Linux kernel (not underneath it). That''s a pretty basic explanation, and I''m sure I''m not quite accurate on it and that some of the other, more knowledgeable folks around here would have better explanations. Both Xen and KVM use Qemu for the interface to the virtual machines (domains), so feature set it going to be pretty similar between the two as far as what kind of hardware you can present, etc. However, the point still stands: determining which one is "better" is something that most likely depends on what you''re trying to do. -Nick>>> On 2010/04/21 at 15:08, Arpan Jindal <jindalarpan@gmail.com> wrote: > I have been using Xen on RHEL from last 3+ years but today i was seeing some > one using KVM on RHEL and, that lead me to ask all which one is better and > how . > > so basically i mean to ask what features xen does have over KVM if any or > both same ? > > > > On Thu, Apr 22, 2010 at 2:20 AM, Nick Couchman <Nick.Couchman@seakr.com>wrote: > >> That depends on who you ask and what you''re doing. You''re asking that >> question on a Xen mailing list, so I''d venture a guest that most of us here >> (yes, us, as in, me too) are going to feel that Xen is a better choice. >> >> What are you trying to accomplish in terms of virutalization? >> >> -Nick >> >> >>> On 2010/04/21 at 11:20, Arpan Jindal <jindalarpan@gmail.com> wrote: >> > Hello all >> > >> > needed your views and review on which one is better on RHEL xen or kvm ? >> >> >> >> >> -------- >> This e-mail may contain confidential and privileged material for the sole >> use of the intended recipient. If this email is not intended for you, or >> you are not responsible for the delivery of this message to the intended >> recipient, please note that this message may contain SEAKR Engineering >> (SEAKR) Privileged/Proprietary Information. In such a case, you are >> strictly prohibited from downloading, photocopying, distributing or >> otherwise using this message, its contents or attachments in any way. If >> you have received this message in error, please notify us immediately by >> replying to this e-mail and delete the message from your mailbox. >> Information contained in this message that does not relate to the business >> of SEAKR is neither endorsed by nor attributable to SEAKR. >>-------- This e-mail may contain confidential and privileged material for the sole use of the intended recipient. If this email is not intended for you, or you are not responsible for the delivery of this message to the intended recipient, please note that this message may contain SEAKR Engineering (SEAKR) Privileged/Proprietary Information. In such a case, you are strictly prohibited from downloading, photocopying, distributing or otherwise using this message, its contents or attachments in any way. If you have received this message in error, please notify us immediately by replying to this e-mail and delete the message from your mailbox. Information contained in this message that does not relate to the business of SEAKR is neither endorsed by nor attributable to SEAKR. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Thu, 22 Apr 2010, Arpan Jindal wrote:> I have been using Xen on RHEL from last 3+ years but today i was seeing some > one using KVM on RHEL and, that lead me to ask all which one is better and > how . > > so basically i mean to ask what features xen does have over KVM if any or > both same ?Today as far as features they are about the same. I still love Xen, but we moved production from all xen boxes to OpenVZ/KVM boxes. We found that OpenVZ does a MUCH better job with our para workloads. The KVM change came simple because it is part of newer kernels and that makes it easier to integrate OpenVZ in rather then trying to get OpenVZ and Xen patches to play nice on newer kernels.><>Nathan Stratton CTO, BlinkMind, Inc. nathan at robotics.net nathan at blinkmind.com http://www.robotics.net http://www.blinkmind.com _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Like others have already said, you''ve asked this question on a Xen list, and you may want to ask on a RHEL or KVM list to get another viewpoint. We use Xen today extensively. For what it''s worth, here are my observations and opinions in no particular order: - If you use a commercial cloud provider like Amazon EC2 or Rackspace Cloud, you probably already use Xen (at least the domU) and may not have a choice. - Xen supports paravirtualization without qemu assistance and without hardware support. This may be an advantage if you are on older hardware, or wish to tailor a stripped-down distribution to run as a domU (e.g. you can build a Linux paravirt kernel without most hardware drivers, or a stubdom based on miniOS). It''s fascinating to me how truly small yet functional a domU can be. - The Linux kernel is big. Very big. I don''t have a technical argument not to place the hypervisor inside Linux (as in KVM) but find it more aesthetically satisfying to separate the hypervisor from the kernel. The Xen hypervisor is quite small, consisting of a text section under 900KB on my x86-64 hardware. (I also wish Linux were smaller but don''t see that trend reversing soon.) - The Xen hypervisor has its own scheduler that runs independent of the Linux process scheduler, potentially yielding more flexibility in system configuration and optimization. KVM however relies on the Linux process scheduler to switch domains, as I understand it. (I''ll avoid arguments whether the Xen or KVM/Linux scheduler is superior for typical workloads.) - The argument that KVM is integrated with the kernel and Xen is not is becoming moot. Thanks to new pv_ops kernels and Jeremy Fitzhardinge''s efforts to merge with the upstream kernel, Xen will soon be as usable with the latest kernels as KVM. - Red Hat''s reasons for embracing KVM seem odd, and possibly a little bit of "NIH" syndrome. With enough work I''m certain KVM can be as good as Xen, or better, in terms of features and support. Whatever problem they had with Xen, are we supposed to believe finishing KVM was less effort than merging Xen? In the end I don''t know that we needed two hypervisors that are so similar, but we have them. It''s going to come down to something like choosing between Intel or AMD. One might have a slight edge over the other at any moment, or be somehow more elegant than the other, but both are very capable and you can do a lot with them. Jeff From: xen-users-bounces@lists.xensource.com [mailto:xen-users-bounces@lists.xensource.com] On Behalf Of Arpan Jindal Sent: Wednesday, April 21, 2010 1:20 PM To: Xen List Subject: [Xen-users] RHEL xen vs kvm Hello all needed your views and review on which one is better on RHEL xen or kvm ? _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Wed, Apr 21, 2010 at 7:26 PM, Jeff Sturm <jeff.sturm@eprize.com> wrote:> > > > In the end I don''t know that we needed two hypervisors that are so similar, > but we have them. It''s going to come down to something like choosing > between Intel or AMD. One might have a slight edge over the other at any > moment, or be somehow more elegant than the other, but both are very capable > and you can do a lot with them. > > > > Jeff > > >At some point (and we''re fast getting there) we''ll be able to apply Linus'' quote about the kernel not mattering to hypervisors. About now the hypervisor is starting to not matter and how you manage your VMs is the real reason to choose which system you use. Currently I only use Paravirtualization because it''s about as fast as bare metal (databases are the worst for virtualization and mysqlbench shows performance within 1% of bare metal) and if you set them up with their own kernel inside the VM disk it looks and acts like a real Linux server. The other mode with Xen is HVM which is full virtualization and is necessary to virtualize Windows. KVM does a better job of this then Xen and is faster for full virt. However KVM isn''t as fast as Xen PV even with KVM PV drivers. It all depends on what your needs are. If we go by the Xen summit slides the future of Xen is in hybrid virtualization which uses hardware virtualization for everything the hardware supports and then uses paravirtualization for everything else. This will be the best of both worlds (HVM and PV). I don''t see KVM moving away from what it''s doing (using Qemu for a lot of stuff, Hardware VT and paravirtualized network and disk drivers). How much of a difference this will make I''m not sure. Here''s my thoughts. If I were primarily virtualizing Windows I''d use KVM. If I were primarily virtualizing Linux I''d use Xen. If I was using a bunch of old 3.4 Ghz Dual Core Xeons (I am) I''d use Xen. If I was wanting to nest VMs I''d use AMD CPUs and KVM (for now). If I wanted the most pain free path to keeping my hypervisor updated I''d use KVM. If I was doing desktop virtualization (local login, not network logins) I''d use KVM or VirtualBox If I wanted the most tried and true enterprise hypervisor out there and didn''t want to use VMWARE then I''d use Xen. Citrix Xenserver, VirtualIron, Sun SVM (one flavor), Oracle Virtual Machine and Amazon EC2 are all based on Xen. It might look like I lean toward KVM from this list but I still prefer Xen in most cases because of category 2. Grant McWilliams _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Well, Xen is "owned" by Citrix, so I assume if Xen was the only one virtualization tool in RHEL, whole virtualisation capatibilities would depend on "another company" and I guess that''s something people in RH didn''t find acceptable. I don''t know the whole story, but many RH customers are approaching them with requests to have something like VmWare offerings (not that they are not satisfied with VmWare functionality and performance, but it''s always viable not to depend on single vendor (especially when the pricing is rather steep)). It doesn''t make me happy that RH is abandoning Xen platform as host system, but it has its share of logic. Anyway, RHEL 6 beta is out, so we can look what''s new with KVM in RHEL - and Xen guest role is still supported (http://www.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6-Beta/html/Beta_Release_Notes/virtualization.html#id569407 - as PVM and as HVM with PV drivers). :) In the end, I guess Xen can benefit from some of KVM and QEMU improvements and ideas. And the better Xen and KVM gets, the better for us all, rigt? :) Regards Matej -----Original Message----- From: xen-users-bounces@lists.xensource.com [mailto:xen-users-bounces@lists.xensource.com] On Behalf Of Jeff Sturm Sent: Thursday, April 22, 2010 4:26 AM To: Arpan Jindal; Xen List Subject: RE: [Xen-users] RHEL xen vs kvm Like others have already said, you''ve asked this question on a Xen list, and you may want to ask on a RHEL or KVM list to get another viewpoint. We use Xen today extensively. For what it''s worth, here are my observations and opinions in no particular order: - If you use a commercial cloud provider like Amazon EC2 or Rackspace Cloud, you probably already use Xen (at least the domU) and may not have a choice. - Xen supports paravirtualization without qemu assistance and without hardware support. This may be an advantage if you are on older hardware, or wish to tailor a stripped-down distribution to run as a domU (e.g. you can build a Linux paravirt kernel without most hardware drivers, or a stubdom based on miniOS). It''s fascinating to me how truly small yet functional a domU can be. - The Linux kernel is big. Very big. I don''t have a technical argument not to place the hypervisor inside Linux (as in KVM) but find it more aesthetically satisfying to separate the hypervisor from the kernel. The Xen hypervisor is quite small, consisting of a text section under 900KB on my x86-64 hardware. (I also wish Linux were smaller but don''t see that trend reversing soon.) - The Xen hypervisor has its own scheduler that runs independent of the Linux process scheduler, potentially yielding more flexibility in system configuration and optimization. KVM however relies on the Linux process scheduler to switch domains, as I understand it. (I''ll avoid arguments whether the Xen or KVM/Linux scheduler is superior for typical workloads.) - The argument that KVM is integrated with the kernel and Xen is not is becoming moot. Thanks to new pv_ops kernels and Jeremy Fitzhardinge''s efforts to merge with the upstream kernel, Xen will soon be as usable with the latest kernels as KVM. - Red Hat''s reasons for embracing KVM seem odd, and possibly a little bit of "NIH" syndrome. With enough work I''m certain KVM can be as good as Xen, or better, in terms of features and support. Whatever problem they had with Xen, are we supposed to believe finishing KVM was less effort than merging Xen? In the end I don''t know that we needed two hypervisors that are so similar, but we have them. It''s going to come down to something like choosing between Intel or AMD. One might have a slight edge over the other at any moment, or be somehow more elegant than the other, but both are very capable and you can do a lot with them. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
From: xen-users-bounces@lists.xensource.com [mailto:xen-users-bounces@lists.xensource.com] On Behalf Of Grant McWilliams Sent: Thursday, April 22, 2010 02:43 To: Jeff Sturm Cc: Arpan Jindal; Xen List Subject: Re: [Xen-users] RHEL xen vs kvm At some point (and we''re fast getting there) we''ll be able to apply Linus'' quote about the kernel not mattering to hypervisors. About now the hypervisor is starting to not matter and how you manage your VMs is the real reason to choose which system you use. Currently I only use Paravirtualization because it''s about as fast as bare metal (databases are the worst for virtualization and mysqlbench shows performance within 1% of bare metal) and if you set them up with their own kernel inside the VM disk it looks and acts like a real Linux server. The other mode with Xen is HVM which is full virtualization and is necessary to virtualize Windows. KVM does a better job of this then Xen and is faster for full virt. However KVM isn''t as fast as Xen PV even with KVM PV drivers. It all depends on what your needs are. If we go by the Xen summit slides the future of Xen is in hybrid virtualization which uses hardware virtualization for everything the hardware supports and then uses paravirtualization for everything else. This will be the best of both worlds (HVM and PV). I don''t see KVM moving away from what it''s doing (using Qemu for a lot of stuff, Hardware VT and paravirtualized network and disk drivers). How much of a difference this will make I''m not sure. Here''s my thoughts. If I were primarily virtualizing Windows I''d use KVM. If I were primarily virtualizing Linux I''d use Xen. If I was using a bunch of old 3.4 Ghz Dual Core Xeons (I am) I''d use Xen. If I was wanting to nest VMs I''d use AMD CPUs and KVM (for now). If I wanted the most pain free path to keeping my hypervisor updated I''d use KVM. If I was doing desktop virtualization (local login, not network logins) I''d use KVM or VirtualBox If I wanted the most tried and true enterprise hypervisor out there and didn''t want to use VMWARE then I''d use Xen. Citrix Xenserver, VirtualIron, Sun SVM (one flavor), Oracle Virtual Machine and Amazon EC2 are all based on Xen. It might look like I lean toward KVM from this list but I still prefer Xen in most cases because of category 2. Grant McWilliams I don’t spend the majority of my time messing with this, but I do follow the list, and I can share my thoughts and experience. My thoughts are that yes, a hypervisor should be better, it is compact and shouldn’t have as many potential security flaws, so shouldn’t need upgraded as often. Simple or not, each upgrade brings potential new problems, so stick with a stable hypervisor unless you need to fix a security issue, are seeking new features, or are squashing a bug. My experience is I am running 4 Windows VMs on the version of Xen included with Fedora 8. Obviously most people can ‘t do this because it isn’t supported and is rather old, but when I started setting up, CentOS didn’t include the drivers I needed, and I didn’t need any newer features that weren’t already available. Since my dom0 and VMs aren’t exposed to the outside world, I didn’t need to worry as much about the latest security updates. My reasons may be way out of date now, but at the time, I was able to get better performance in Windows out of Xen using the GPLPV drivers, and unless additional drivers have been developed for KVM in the past few years, I don’t see how fully virtualized KVM machines could be faster than Xen HVM machines using PV drivers. In addition to being able to get better performance in Windows on Xen, I found it easier to automatically start everything in Xen (I don’t KNOW that KVM’s virtual machines can’t run without a user logged in, but I don’t know how to make it do it, and I don ‘t know how to make a user automatically log in, nor do I think I should have to, nor do I want my VMs associated with a user), perhaps this is only because I had more experience with Xen and spent less time researching KVM than I could have (but then, why keep researching when the solution I’m more familiar with performs better as well?). Anyway, that sums up my experience and the reasons for making the choices I did (F8 even though it was toward EOL and Xen even though I’m running Windows). Dustin _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Thu, Apr 22, 2010 at 6:22 AM, Dustin Henning <Dustin.Henning@prd-inc.com>wrote:> > ** ** > > The other mode with Xen is HVM which is full virtualization and is > necessary to virtualize Windows. KVM does a better job of this then Xen and > is faster for full virt. However KVM isn''t as fast as Xen PV even with KVM > PV drivers. It > > > It might look like I lean toward KVM from this list but I still prefer Xen > in most cases because of category 2. > > Grant McWilliams > > > > I don’t spend the majority of my time messing with this, but I do follow > the list, and I can share my thoughts and experience. My thoughts are that > yes, a hypervisor should be better, it is compact and shouldn’t have as many > potential security flaws, so shouldn’t need upgraded as often. Simple or > not, each upgrade brings potential new problems, so stick with a stable > hypervisor unless you need to fix a security issue, are seeking new > features, or are squashing a bug. >Agreed.> I was able to get better performance in Windows out of Xen using the GPLPV > drivers, and unless additional drivers have been developed for KVM in the > past few years, I don’t see how fully virtualized KVM machines could be > faster than Xen HVM machines using PV drivers. >KVM uses PV drivers as well in addition to taking advantage of newer versions of qemu then Xen. Xen always seems to merge qemu slower. Xen also has other architecture problems in that data has to travel from DomU to the hypervisor to Dom0 to pass through the drivers and then out. With KVM each guest acts like an application running and has more direct access to hardware. I see a fairly large DomU to DomU network performance hit too but only in one direction in Xen. I don''t think we''ve ever really tracked that down. However, KVM uses virtio which has a performance hit over the Xen rebased kernel. Xen will inherit this performance hit though when we move to the pvops kernal. At that point the optimizations done to virtio will effect both hypervisors. It''s not known how big this hit is quite yet but Intel was throwing around 5% numbers. One thing that hasn''t been addressed though is security. Xen is the most secure Virtualization platform out there. There are still vulnerabilities but it''s in the lead for security. In order to get KVM to be anywhere near as secure you will need to rely heavily on SELinux. I think in the coming two years none of this will matter and we''ll be focusing on how you manage VMs, this change is already happening in the industry as Citrix is supporting XenServer and HyperV with their software.> Dustin >Grant McWilliams _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
> -----Original Message----- > From: xen-users-bounces@lists.xensource.com [mailto:xen-users- > bounces@lists.xensource.com] On Behalf Of Matej Zary > Sent: Thursday, April 22, 2010 4:09 AM > To: xen-users@lists.xensource.com > Subject: RE: [Xen-users] RHEL xen vs kvm > > Well, Xen is "owned" by Citrix, so I assume if Xen was the only onevirtualization tool in> RHEL, whole virtualisation capatibilities would depend on "anothercompany" and I> guess that''s something people in RH didn''t find acceptable.Trouble is, I don''t see Red Hat becoming a major virtualization player. They trail too far behind VMWare, Citrix and even Microsoft. Other companies have solved this with technology partnerships. Red Hat chose to acquire an underdog instead. We''ll see in a few years how that works out for them.> In the end, I guess Xen can benefit from some of KVM and QEMU > improvements and ideas. And the better Xen and KVM gets, the betterfor us all, rigt? Indeed. Competition and fair market -> customer wins. Jeff _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
> Other companies have solved this with technology partnerships. Red Hat > chose to acquire an underdog instead. We''ll see in a few years how that > works out for them.I wonder about the fallout of this in CentOS land. We run RHEL everywhere but CentOS for the hypervisors because of RHEL''s Xen restrictions (that whole "advanced platform" thing). Where is CentOS going to take this? Here''s to hoping they continue to support Xen. John -- John Madden Sr UNIX Systems Engineer Ivy Tech Community College of Indiana jmadden@ivytech.edu _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Thu, Apr 22, 2010 at 02:38:21AM +0530, Arpan Jindal wrote:> I have been using Xen on RHEL from last 3+ years but today i > was seeing some one using KVM on RHEL and, that lead me to ask all which > one is better and how . > so basically i mean to ask what features xen does have over KVM if any or > both same ? >Xen is a secure, high-performance true type-1 baremetal hypervisor, while KVM is a loadable module for Linux, so kvm is basicly a type-2 hosted hypervisor. -- Pasi> On Thu, Apr 22, 2010 at 2:20 AM, Nick Couchman > <[1]Nick.Couchman@seakr.com> wrote: > > That depends on who you ask and what you''re doing. You''re asking that > question on a Xen mailing list, so I''d venture a guest that most of us > here (yes, us, as in, me too) are going to feel that Xen is a better > choice. > > What are you trying to accomplish in terms of virutalization? > > -Nick > >>> On 2010/04/21 at 11:20, Arpan Jindal <[2]jindalarpan@gmail.com> > wrote: > > Hello all > > > > needed your views and review on which one is better on RHEL xen or kvm > ? > > -------- > This e-mail may contain confidential and privileged material for the > sole use of the intended recipient. If this email is not intended for > you, or you are not responsible for the delivery of this message to the > intended recipient, please note that this message may contain SEAKR > Engineering (SEAKR) Privileged/Proprietary Information. In such a case, > you are strictly prohibited from downloading, photocopying, distributing > or otherwise using this message, its contents or attachments in any way. > If you have received this message in error, please notify us > immediately by replying to this e-mail and delete the message from your > mailbox. Information contained in this message that does not relate to > the business of SEAKR is neither endorsed by nor attributable to SEAKR. > > References > > Visible links > 1. mailto:Nick.Couchman@seakr.com > 2. mailto:jindalarpan@gmail.com> _______________________________________________ > Xen-users mailing list > Xen-users@lists.xensource.com > http://lists.xensource.com/xen-users_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Wed, Apr 21, 2010 at 11:42:31PM -0700, Grant McWilliams wrote:> On Wed, Apr 21, 2010 at 7:26 PM, Jeff Sturm <[1]jeff.sturm@eprize.com> > wrote: > >  > > In the end I don''t know that we needed two hypervisors that are so > similar, but we have them. It''s going to come down to something like > choosing between Intel or AMD. One might have a slight edge over the > other at any moment, or be somehow more elegant than the other, but both > are very capable and you can do a lot with them. > >  > > Jeff > >  > > At some point (and we''re fast getting there) we''ll be able to apply Linus'' > quote about the kernel not mattering to hypervisors. About now the > hypervisor is starting to not matter and how you manage your VMs is the > real reason to choose which system you use. > > Currently I only use Paravirtualization because it''s about as fast as bare > metal (databases are the worst for virtualization and mysqlbench shows > performance within 1% of bare metal) and if you set them up with their own > kernel inside the VM disk it looks and acts like a real Linux server. The > other mode with Xen is HVM which is full virtualization and is necessary > to virtualize Windows. KVM does a better job of this then Xen and is > faster for full virt. >Do you have some benchmarks to prove KVM being faster than Xen HVM?> However KVM isn''t as fast as Xen PV even with KVM PV > drivers. It all depends on what your needs are. If we go by the Xen summit > slides the future of Xen is in hybrid virtualization which uses hardware > virtualization for everything the hardware supports and then uses > paravirtualization for everything else. This will be the best of both > worlds (HVM and PV). I don''t see KVM moving away from what it''s doing > (using Qemu for a lot of stuff, Hardware VT and paravirtualized network > and disk drivers). How much of a difference this will make I''m not sure. > > Here''s my thoughts. > If I were primarily virtualizing Windows I''d use KVM.Why? Xen has both the GPLPV Windows drivers, and the binary WHQL Citrix Windows PV drivers available today.> If I were primarily virtualizing Linux I''d use Xen. > If I was using a bunch of old 3.4 Ghz Dual Core Xeons (I am) I''d use Xen. > If I was wanting to nest VMs I''d use AMD CPUs and KVM (for now). >Xen also now has patches to supported Nested virtualization on both Intel and AMD. I bet this will end up in the Xen 4.1 development tree in upcoming weeks.> If I wanted the most pain free path to keeping my hypervisor updated I''d > use KVM. > If I was doing desktop virtualization (local login, not network logins) > I''d use KVM or VirtualBox > If I wanted the most tried and true enterprise hypervisor out there and > didn''t want to use VMWARE then I''d use Xen. Citrix Xenserver, VirtualIron, > Sun SVM (one flavor), Oracle Virtual Machine and Amazon EC2 are all based > on Xen. > It might look like I lean toward KVM from this list but I still prefer Xen > in most cases because of category 2. >There are a lot of options for Xen dom0 kernel nowadays.. although extra patching or fetching the git tree is still needed. http://wiki.xensource.com/xenwiki/XenDom0Kernels -- Pasi _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Thu, Apr 29, 2010 at 9:53 AM, Pasi Kärkkäinen <pasik@iki.fi> wrote:> On Wed, Apr 21, 2010 at 11:42:31PM -0700, Grant McWilliams wrote: > > On Wed, Apr 21, 2010 at 7:26 PM, Jeff Sturm <[1]jeff.sturm@eprize.com > > > > > > > Do you have some benchmarks to prove KVM being faster than Xen HVM? >Yes, I do. I''ve been gathering statistics for quite a while because I''m writing a white paper on Linux Virtualization Performance. I''ll need to dig them up after I get back from work. The difference is enough to sway the decision if someone was only going to virtualize Windows. If someone were to just use PV though Xen wins hands down.> > Here''s my thoughts. > If I were primarily virtualizing Windows I''d use KVM.Why? Xen has both the GPLPV Windows drivers, and the binary WHQL Citrix> Windows > PV drivers available today. >You''d think wouldn''t you? I don''t think it has to do with two drivers.> > If I were primarily virtualizing Linux I''d use Xen. > > If I was using a bunch of old 3.4 Ghz Dual Core Xeons (I am) I''d use > Xen. > > If I was wanting to nest VMs I''d use AMD CPUs and KVM (for now). > > > > Xen also now has patches to supported Nested virtualization on both Intel > and AMD. > I bet this will end up in the Xen 4.1 development tree in upcoming weeks. >I will be looking forward to this indeed. I don''t want to change my platform just because I need one thing. How is it going to support nesting on Intel? I was under the impression that AMD was the one that supported this in hardware.> > > If I wanted the most pain free path to keeping my hypervisor updated > I''d > > use KVM. > > If I was doing desktop virtualization (local login, not network > logins) > > I''d use KVM or VirtualBox > > If I wanted the most tried and true enterprise hypervisor out there > and > > didn''t want to use VMWARE then I''d use Xen. Citrix Xenserver, > VirtualIron, > > Sun SVM (one flavor), Oracle Virtual Machine and Amazon EC2 are all > based > > on Xen. > > It might look like I lean toward KVM from this list but I still prefer > Xen > > in most cases because of category 2. > > > > There are a lot of options for Xen dom0 kernel nowadays.. although extra > patching > or fetching the git tree is still needed. >Lots of options? You mean like compiling your own kernel? Pain free means running your distribution the way it came. I predict in the coming years we''ll have two options - running XCP or running XenServer. I''m not sure how well either put out security patches.> > http://wiki.xensource.com/xenwiki/XenDom0Kernels > > -- Pasi > >Grant _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Thu, Apr 29, 2010 at 11:03:55AM -0700, Grant McWilliams wrote:> On Thu, Apr 29, 2010 at 9:53 AM, Pasi KÀrkkÀinen <[1]pasik@iki.fi> > wrote: > > On Wed, Apr 21, 2010 at 11:42:31PM -0700, Grant McWilliams wrote: > >   On Wed, Apr 21, 2010 at 7:26 PM, Jeff Sturm > <[1][2]jeff.sturm@eprize.com> > > > > Do you have some benchmarks to prove KVM being faster than Xen HVM? > > Yes, I do. I''ve been gathering statistics for quite a while because I''m > writing a white paper on Linux Virtualization Performance. > I''ll need to dig them up after I get back from work. The difference is > enough to sway the decision if someone was only going to virtualize > Windows. If someone were to just use PV though Xen wins hands down. >I''m really surprised if there is a big difference between Xen HVM vs. KVM. What software versions did you use? What kind of hardware? I''m sure Citrix Xen guys want to see the results and comment if there''s something to tweak :)> > > >   Here''s my thoughts. > >   If I were primarily virtualizing Windows I''d use KVM. > > Why? Xen has both the GPLPV Windows drivers, and the binary WHQL Citrix > Windows > PV drivers available today. > > You''d think wouldn''t you? I don''t think it has to do with two drivers. >What are the reasons then? ;)> > >   If I were primarily virtualizing Linux I''d use Xen. > >   If I was using a bunch of old 3.4 Ghz Dual Core Xeons (I am) I''d > use Xen. > >   If I was wanting to nest VMs I''d use AMD CPUs and KVM (for now). > > > > Xen also now has patches to supported Nested virtualization on both > Intel and AMD. > I bet this will end up in the Xen 4.1 development tree in upcoming > weeks. > > I will be looking forward to this indeed. I don''t want to change my > platform just because I need one thing. > How is it going to support nesting on Intel? I was under the impression > that AMD was the one that supported > this in hardware.See the patches posted to xen-devel last week by Intel.> > >   If I wanted the most pain free path to keeping my hypervisor > updated I''d > >   use KVM. > >   If I was doing desktop virtualization (local login, not network > logins) > >   I''d use KVM or VirtualBox > >   If I wanted the most tried and true enterprise hypervisor out > there and > >   didn''t want to use VMWARE then I''d use Xen. Citrix Xenserver, > VirtualIron, > >   Sun SVM (one flavor), Oracle Virtual Machine and Amazon EC2 are > all based > >   on Xen. > >   It might look like I lean toward KVM from this list but I still > prefer Xen > >   in most cases because of category 2. > > > > There are a lot of options for Xen dom0 kernel nowadays.. although extra > patching > or fetching the git tree is still needed. > > Lots of options? You mean like compiling your own kernel? Pain free means > running your distribution the way it came. I predict in the coming years > we''ll have two options - running XCP or running XenServer. I''m not sure > how well either put out security patches. >Yeah, XCP or XenServer is an easy solution if you don''t want to buid your own platform. -- Pasi _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Thu, Apr 29, 2010 at 09:40:39PM +0300, Pasi Kärkkäinen wrote:> On Thu, Apr 29, 2010 at 11:03:55AM -0700, Grant McWilliams wrote: > > On Thu, Apr 29, 2010 at 9:53 AM, Pasi KÀrkkÀinen <[1]pasik@iki.fi> > > wrote: > > > > On Wed, Apr 21, 2010 at 11:42:31PM -0700, Grant McWilliams wrote: > > >   On Wed, Apr 21, 2010 at 7:26 PM, Jeff Sturm > > <[1][2]jeff.sturm@eprize.com> > > > > > > > Do you have some benchmarks to prove KVM being faster than Xen HVM? > > > > Yes, I do. I''ve been gathering statistics for quite a while because I''m > > writing a white paper on Linux Virtualization Performance. > > I''ll need to dig them up after I get back from work. The difference is > > enough to sway the decision if someone was only going to virtualize > > Windows. If someone were to just use PV though Xen wins hands down. > > > > I''m really surprised if there is a big difference between Xen HVM vs. KVM. > > What software versions did you use? > What kind of hardware? > > I''m sure Citrix Xen guys want to see the results and comment if there''s something to tweak :) >Replying to myself.. Grant: I''m not sure if you replied to this.. I had some trouble with my email provider getting blacklisted because of some spam problems. -- Pasi> > > > > > >   Here''s my thoughts. > > >   If I were primarily virtualizing Windows I''d use KVM. > > > > Why? Xen has both the GPLPV Windows drivers, and the binary WHQL Citrix > > Windows > > PV drivers available today. > > > > You''d think wouldn''t you? I don''t think it has to do with two drivers. > > > > What are the reasons then? ;) > > > > > > >   If I were primarily virtualizing Linux I''d use Xen. > > >   If I was using a bunch of old 3.4 Ghz Dual Core Xeons (I am) I''d > > use Xen. > > >   If I was wanting to nest VMs I''d use AMD CPUs and KVM (for now). > > > > > > > Xen also now has patches to supported Nested virtualization on both > > Intel and AMD. > > I bet this will end up in the Xen 4.1 development tree in upcoming > > weeks. > > > > I will be looking forward to this indeed. I don''t want to change my > > platform just because I need one thing. > > How is it going to support nesting on Intel? I was under the impression > > that AMD was the one that supported > > this in hardware. > > See the patches posted to xen-devel last week by Intel. > > > > > > >   If I wanted the most pain free path to keeping my hypervisor > > updated I''d > > >   use KVM. > > >   If I was doing desktop virtualization (local login, not network > > logins) > > >   I''d use KVM or VirtualBox > > >   If I wanted the most tried and true enterprise hypervisor out > > there and > > >   didn''t want to use VMWARE then I''d use Xen. Citrix Xenserver, > > VirtualIron, > > >   Sun SVM (one flavor), Oracle Virtual Machine and Amazon EC2 are > > all based > > >   on Xen. > > >   It might look like I lean toward KVM from this list but I still > > prefer Xen > > >   in most cases because of category 2. > > > > > > > There are a lot of options for Xen dom0 kernel nowadays.. although extra > > patching > > or fetching the git tree is still needed. > > > > Lots of options? You mean like compiling your own kernel? Pain free means > > running your distribution the way it came. I predict in the coming years > > we''ll have two options - running XCP or running XenServer. I''m not sure > > how well either put out security patches. > > > > Yeah, XCP or XenServer is an easy solution if you don''t want to buid your > own platform. > > -- Pasi >_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Thu, May 13, 2010 at 5:49 AM, Pasi Kärkkäinen <pasik@iki.fi> wrote:> On Thu, Apr 29, 2010 at 09:40:39PM +0300, Pasi Kärkkäinen wrote: > > On Thu, Apr 29, 2010 at 11:03:55AM -0700, Grant McWilliams wrote: > > > On Thu, Apr 29, 2010 at 9:53 AM, Pasi KÀrkkÀinen <[1]pasik@iki.fi > > > > > wrote: > > > > > > On Wed, Apr 21, 2010 at 11:42:31PM -0700, Grant McWilliams wrote: > > > >   On Wed, Apr 21, 2010 at 7:26 PM, Jeff Sturm > > > <[1][2]jeff.sturm@eprize.com> > > > > > > > > > > Do you have some benchmarks to prove KVM being faster than Xen > HVM? > > > > > > Yes, I do. I''ve been gathering statistics for quite a while because > I''m > > > writing a white paper on Linux Virtualization Performance. > > > I''ll need to dig them up after I get back from work. The difference > is > > > enough to sway the decision if someone was only going to virtualize > > > Windows. If someone were to just use PV though Xen wins hands down. > > > > > > > I''m really surprised if there is a big difference between Xen HVM vs. > KVM. > > > > What software versions did you use? > > What kind of hardware? > > > > I''m sure Citrix Xen guys want to see the results and comment if there''s > something to tweak :) > > > > Replying to myself.. > > Grant: I''m not sure if you replied to this.. I had some trouble with my > email provider > getting blacklisted because of some spam problems. > > My last response was this... I''m working 110 hrs a week and teaching twocollege classes. I''ll get back to this topic! For now. I predict (and you can quote me) that Xen Dom0 will be removed in all big distros in time. Mind you I don''t want this because I use it exclusively for my server virtualization needs. The reason for this is if KVM provides 95% of what Xen does and is already included and it''s easy for the packagers to maintain then everyone will move to it. Every year at LinuxFest NW I hear the Redhat people complaining about how hard it is to get the Xen patches to work on newer kernels. As of RHEL6 those complaints have gone away because Xen Dom0 support is gone. Suse would probably like to stop doing the work they''re doing as well. By the time Xen Dom0 will be in the mainline kernel nobody will care anymore. I think a shift in mentality is in order. We''re not trying to get VMware ESX in the kernel, if we want to use it we download the CD and install it. I think this is where Xen will end up. XCP and XenServer are already there. Grant _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Thu, May 13, 2010 at 06:57:46AM -0700, Grant McWilliams wrote:> On Thu, May 13, 2010 at 5:49 AM, Pasi KÀrkkÀinen <[1]pasik@iki.fi> > wrote: > > On Thu, Apr 29, 2010 at 09:40:39PM +0300, Pasi KÀrkkÀinen wrote: > > On Thu, Apr 29, 2010 at 11:03:55AM -0700, Grant McWilliams wrote: > > >   On Thu, Apr 29, 2010 at 9:53 AM, Pasi KÃ*â*¬rkkÃ*â*¬inen > <[1][2]pasik@iki.fi> > > >   wrote: > > > > > >    On Wed, Apr 21, 2010 at 11:42:31PM -0700, Grant McWilliams > wrote: > > >    > Ã*  Ã* On Wed, Apr 21, 2010 at 7:26 PM, Jeff Sturm > > >    <[1][2][3]jeff.sturm@eprize.com> > > >    > > > > > > >    Do you have some benchmarks to prove KVM being faster than > Xen HVM? > > > > > >   Yes, I do. I''ve been gathering statistics for quite a while > because I''m > > >   writing a white paper on Linux Virtualization Performance. > > >   I''ll need to dig them up after I get back from work. The > difference is > > >   enough to sway the decision if someone was only going to > virtualize > > >   Windows. If someone were to just use PV though Xen wins hands > down. > > > > > > > I''m really surprised if there is a big difference between Xen HVM vs. > KVM. > > > > What software versions did you use? > > What kind of hardware? > > > > I''m sure Citrix Xen guys want to see the results and comment if > there''s something to tweak :) > > > > Replying to myself.. > > Grant: I''m not sure if you replied to this.. I had some trouble with my > email provider > getting blacklisted because of some spam problems. > > My last response was this... I''m working 110 hrs a week and teaching two > college classes. I''ll get back to this topic! >Ok. No problems, take your time :)> For now. I predict (and you can quote me) that Xen Dom0 will be removed in > all big distros in time. > Mind you I don''t want this because I use it exclusively for my server > virtualization needs. The reason > for this is if KVM provides 95% of what Xen does and is already included > and it''s easy for the packagers > to maintain then everyone will move to it. Every year at LinuxFest NW I > hear the Redhat people complaining about > how hard it is to get the Xen patches to work on newer kernels. As of > RHEL6 those complaints have gone away because > Xen Dom0 support is gone. Suse would probably like to stop doing the work > they''re doing as well. By the time > Xen Dom0 will be in the mainline kernel nobody will care anymore. >See: http://blog.xen.org/index.php/2010/05/07/xen-%E2%80%93-kvm-linux-%E2%80%93-and-the-community/> I think a shift in mentality is in order. We''re not trying to get VMware > ESX in the kernel, if we want to use it we download > the CD and install it. I think this is where Xen will end up. XCP and > XenServer are already there. >Yeah, hypervisors are already commodity, so people will focus more on high-level stuff. Building a virtualization platform on Xen is not a problem for virtualization-vendor, since they can choose from the available kernels (and actually there are a lot of options today), but it might be a problem (atm) for a Linux vendor, who just wants to use the ''upstream'' stuff only. And when talking about Redhat we have to remember they bought KVM for $105M USD or so.. -- Pasi _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
> From: Grant McWilliams [mailto:grantmasterflash@gmail.com] > > I think a shift in mentality is in order. We're not trying > to get VMware ESX in the kernel, if we want to use it we download > the CD and install it. I think this is where Xen will end up. > XCP and XenServer are already there.Yes--that's the key. It seems like a myth prevails among some users that the dom0 and domU should somehow match (distro, version, etc.). That's nonsense of course. Even users who want to stay with RHEL for dom0, whatever the reason, have a perfectly viable option for years to come: RHEL 5. Once RHEL 5 reaches EOL, we'll likely have a plethora of options. Perhaps system manufacturers will be shipping a hypervisor in firmware by then, who knows. (But if not, XCP works too.) Jeff _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users