I have read about another virtualizazion system: KVM. It seems very good and I know about users that have replaced Xen with KVM. What do you think about? _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Tue, Nov 18, 2008 at 12:57 PM, Mauro <mrsanna1@gmail.com> wrote:> I have read about another virtualizazion system: KVM. > It seems very good and I know about users that have replaced Xen with KVM. > What do you think about?choice is good -- Javier _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
for me kvm is working very fast. also kvm have network drivers, and speed is very good On 11/18/2008 4:06 PM, Javier Guerra wrote:> On Tue, Nov 18, 2008 at 12:57 PM, Mauro<mrsanna1@gmail.com> wrote: > >> I have read about another virtualizazion system: KVM. >> It seems very good and I know about users that have replaced Xen with KVM. >> What do you think about? >> > > choice is good > >-- ------------ Itamar Reis Peixoto e-mail/msn: itamar@ispbrasil.com.br sip: itamar@ispbrasil.com.br skype: itamarjp icq: 81053601 +55 11 4063 5033 +55 34 3221 8599 _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
2008/11/18 Javier Guerra <javier@guerrag.com>> On Tue, Nov 18, 2008 at 1:19 PM, Mauro <mrsanna1@gmail.com> wrote: > > From various virtualization systems what do you suggest based on your > > experience? > > you''d get more pointers posting on the lists and not to me privatelySorry, I forget to do a replay-all.> > > the first rule of thumb is kvm on the desktop, xen on the server. but > there are lots and lots of exceptions...O yes ...... I install xen on a server so my choice seems good. I want to create two virtual machines as database servers, the first will be a database server with oracle and mysql, while the second will be a clone of the first one. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
I tried KVM some weeks ago but I just had installed one guest system (Windows 2000 Server). Pros: + nice hardware compatibility (quite newer kernels than 2.6.18 supported) Cons: - afaik no PCI passthrough - still in development and not as stable as Xen My Win2000 Server is far more faster on Xen, maybe this was an issue with the standard interfaces between dom0 and guest. If you can use virtio devices (I think the frontend drivers are included since kernel version 2.6.23 or 2.6.25) there will be no bottle neck anymore. With some kernel hacks I newly got Xen running on my hardware (nvidia 630a chipset). So this will be my personal solution for some month. On a desktop system with newer hardware a KVM system is perhaps the best solution, but on a server I think it''s better to get Xen running. If you have a running Xen system then I don''t see any reason why to change it, considering the stage of developement. Mauro:> I have read about another virtualizazion system: KVM. > It seems very good and I know about users that have replaced Xen with KVM. > What do you think about? > > ------------------------------------------------------------------------ > > _______________________________________________ > 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
Hi, My choice is also shifting towards KVM, especially on desktop (latest kernel, no problem with nvidia drivers, virtio etc.) It''s also catching up on server installations. Emre On Tue, Nov 18, 2008 at 7:36 PM, Mauro <mrsanna1@gmail.com> wrote:> > > 2008/11/18 Javier Guerra <javier@guerrag.com> > >> On Tue, Nov 18, 2008 at 1:19 PM, Mauro <mrsanna1@gmail.com> wrote: >> > From various virtualization systems what do you suggest based on your >> > experience? >> >> you''d get more pointers posting on the lists and not to me privately > > > Sorry, I forget to do a replay-all. > >> >> >> the first rule of thumb is kvm on the desktop, xen on the server. but >> there are lots and lots of exceptions... > > > O yes ...... I install xen on a server so my choice seems good. > I want to create two virtual machines as database servers, the first will > be a database server with oracle and mysql, while the second will be a clone > of the first one. > > > _______________________________________________ > Xen-users mailing list > Xen-users@lists.xensource.com > http://lists.xensource.com/xen-users >-- Emre _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Hi again, On Tue, Nov 18, 2008 at 8:53 PM, Johannes Schlatow < johannes.schlatow@googlemail.com> wrote:> Cons: > - afaik no PCI passthrough > - still in development and not as stable as Xen >Well I don''t see stability problem on my test systems. For PCI passthough, check out this announcement, it''s coming: http://www.linux-kvm.com/content/kvm-79-released-pci-device-assignment-pci-device-hot-plug> > My Win2000 Server is far more faster on Xen, maybe this was an issue > with the standard interfaces between dom0 and guest. If you can use > virtio devices (I think the frontend drivers are included since kernel > version 2.6.23 or 2.6.25) there will be no bottle neck anymore.I find KVM faster. Especially on linux-on-linux virtualizations, KVM with virtio is very fast. Near native in fact. For Windows guest installations, the virtio network driver is also very fast (above gigabit speeds on a Core2Duo). The emulated disk benchmarks (simple benchmarks) were about 60 meg/sec on a raid0 array of two sata disks. I guess it will also be very fast if it can be run over a AoE or iScsi host.> With some kernel hacks I newly got Xen running on my hardware (nvidia > 630a chipset). So this will be my personal solution for some month.very difficult, time consuming, hair trimming. I gave up personally after Ubuntu Hardy (2.6.22 dom0 kernel) and switched to KVM on desktop. Emre _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Tue, Nov 18, 2008 at 3:04 PM, Emre Erenoglu <erenoglu@gmail.com> wrote:> On Tue, Nov 18, 2008 at 8:53 PM, Johannes Schlatow > <johannes.schlatow@googlemail.com> wrote: >> - still in development and not as stable as Xen > > Well I don''t see stability problem on my test systems. For PCI passthough, > check out this announcement, it''s coming: > http://www.linux-kvm.com/content/kvm-79-released-pci-device-assignment-pci-device-hot-plugKVM is in very heavy development, it''s just too tempting to follow the latest release; but there are frequent regressions. if you stay with a supposedly distro-supported, you avoid those, but wait far longer to get the best performance and features. also, usually distro-support was very limited. hopefully this would change now that redhad bought Qumranet. that''s why for the time being, Xen still seems the safest choice for servers. -- Javier _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On November 18, 2008 11:53 am Johannes Schlatow wrote:> I tried KVM some weeks ago but I just had installed one guest system > (Windows 2000 Server). > > Pros: > + nice hardware compatibility (quite newer kernels than 2.6.18 > supported) > > Cons: > - afaik no PCI passthroughPCI Passthrough using Intel VT-D (or whatever they call it these days) has been available in KVM for quite awhile. Was first released somewhere around KVM-70-ish.> - still in development and not as stable as Xen-- Freddie Cash fjwcash@gmail.com _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Tue, Nov 18, 2008 at 12:04 PM, Emre Erenoglu <erenoglu@gmail.com> wrote:> Hi again, > > On Tue, Nov 18, 2008 at 8:53 PM, Johannes Schlatow < > johannes.schlatow@googlemail.com> wrote: > >> Cons: >> - afaik no PCI passthrough >> - still in development and not as stable as Xen >> > > Well I don''t see stability problem on my test systems. For PCI passthough, > check out this announcement, it''s coming: > > http://www.linux-kvm.com/content/kvm-79-released-pci-device-assignment-pci-device-hot-plug > > >> >> My Win2000 Server is far more faster on Xen, maybe this was an issue >> with the standard interfaces between dom0 and guest. If you can use >> virtio devices (I think the frontend drivers are included since kernel >> version 2.6.23 or 2.6.25) there will be no bottle neck anymore. > > > I find KVM faster. Especially on linux-on-linux virtualizations, KVM with > virtio is very fast. Near native in fact. > > For Windows guest installations, the virtio network driver is also very > fast (above gigabit speeds on a Core2Duo). The emulated disk benchmarks > (simple benchmarks) were about 60 meg/sec on a raid0 array of two sata > disks. I guess it will also be very fast if it can be run over a AoE or > iScsi host. > > >> With some kernel hacks I newly got Xen running on my hardware (nvidia >> 630a chipset). So this will be my personal solution for some month. > > > very difficult, time consuming, hair trimming. I gave up personally after > Ubuntu Hardy (2.6.22 dom0 kernel) and switched to KVM on desktop. > > Emre >KVM is NOT in any way ready for a production environment. Just follow the KVM dev list to see what I''m talking about. The Xen dev list is full of small patches and the KVM dev list is chock full or people ripping out the transmission and crankshaft every week. I give it about a year before I''l start moving it into production. With kvm-78 and kvm-79 there was a huge regression in qcow2 disk images to the tune of 1/10 the performance. Yes, that''s about 6MB/sec on a 60MB/sec drive. With kvm-77 you''ll get 60MB/sec on that same disk image. These things happen all the time. And if you want to run KVM on an enterprise Linux (Redhat perhaps) you''re going to get a really old version. Even if you upgrade it you''ll be about 10 version back. You can upgrade Xen to 3.3 fairly easy on RHEL5. Upgrading the kernel to something other than the stock one though is a different story. Linux on Linux should never be faster on KVM but with virtio drivers for disk and net it should be able to equal Xen in those two areas. Xen currently has some IO issues on inbound network traffic that limits it but outbound runs as fast as anything. KVM running fulling virtualized should be faster than Xen though if you need to do that for running Windows etc... Xen however is the most secure VM solution around and with 3.3 and stub domains it got more secure. I follow the KVM dev cycle and use it for test cases but never in a production environment. For Desktop I use VirtualBox and for all servers I use Xen 3.3. Having said all of this I still track KVM development because in time it will be come THE Virtualization for Linux. However, it''s only a Linux solution as it will only run on Linux. Our thinking has a tendency to get a little OS centric sometimes. Grant McWilliams _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Tue, Nov 18, 2008 at 5:44 PM, Grant McWilliams <grantmasterflash@gmail.com> wrote:> Linux on Linux should never be faster on KVM but with virtio drivers for > disk and net it should be able to equal Xen in those two areas. Xen > currently has some IO issues on inbound network traffic that limits it but > outbound runs as fast as anything.KVM has around half the context-switches per packet/block transmitted than Xen, even PV Xen. also, since the final I/O is a separate thread on each VM''s process, it''s easy to tune I/O to your needs with usual Linux tools, even without any tuning, the workload balance seems better than VMWare Server on the same machine. nothing that Xen shouldn''t be able to do, but it''s usually much harder to reach the same raw performance. as said before, choice is good, even for the ''contenders'' -- Javier _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
> > > KVM has around half the context-switches per packet/block transmitted > than Xen, even PV Xen. > > -- > Javier >Do you happen to know how Xen can do a Gb going out the interface but only 360Mb coming in? Grant McWilliams Some people, when confronted with a problem, think "I know, I''ll use Windows." Now they have two problems. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Hi Grant, On Tue, 2008-11-18 at 22:31 -0800, Grant McWilliams wrote:> > > KVM has around half the context-switches per packet/block > transmitted > than Xen, even PV Xen. > > -- > Javier > > Do you happen to know how Xen can do a Gb going out the interface but > only 360Mb coming in?This is (at least) partly due to Xennet acceleration if your talking about PV guests in general. If your using network adapters with tcp offload and iSCSI, part of that bump is due to the hardware, can you describe your hardware and speedup? The last time I looked at it was in 2007, though. At that point in time it was speculative at best if such things could be included in mainline[1], so I''m not sure if we''ll lose that if/when dom-0 ops are accepted. Behold the power of a well written microkernel, err, I mean .. virtual machine monitor :) Cheers, --Tim [1] http://lists.xensource.com/archives/html/xen-devel/2007-10/msg00075.html _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Wed, Nov 19, 2008 at 1:25 AM, Tim Post <echo@echoreply.us> wrote:> Hi Grant, > > On Tue, 2008-11-18 at 22:31 -0800, Grant McWilliams wrote: > > > > > > KVM has around half the context-switches per packet/block > > transmitted > > than Xen, even PV Xen. > > > > -- > > Javier > > > > Do you happen to know how Xen can do a Gb going out the interface but > > only 360Mb coming in? > > This is (at least) partly due to Xennet acceleration if your talking > about PV guests in general. > > If your using network adapters with tcp offload and iSCSI, part of that > bump is due to the hardware, can you describe your hardware and speedup? > > Cheers, > --TimTim, I''m talking PV on CentOS 5.2 Dom0 and CentOS 5.2 DomUs. I''m using Xen 3.3. The machine has Intel Gb/E cards and nothing special. I wanted to benchmark some VMs of various kinds and I noticed that DomU to DomU performance sat at about 360Mb/sec which seemed way off the mark so then I tested DomU to Dom0 and got about 800Mb/sec. After further testing is seems that if the traffic is exiting the DomU then it goes full speed but there''s a slowdown when data is entering the DomU. I''m not sure this is the whole story though as I''ve seen people on this list set up real network cards for each DomU claiming that the performance is better. Grant McWilliams Some people, when confronted with a problem, think "I know, I''ll use Windows." Now they have two problems. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users