Robin van Leeuwen
2005-Aug-31 19:48 UTC
[Xen-users] Question about stability 32bit chroot and xen 2.0.7
I want to run a stable system with Xen, so my best choice is the xen-2.0.7 installation. I have however a AMD opteron which is 64 bit. Will i be able to run a stable Xen server in a 32 bit chroot enviroment on Debian 3.1 amd64 stable? Or would my best bet be, install Debian i386 on my amd64 and run xen-2.0.7 from there. The last option however needs a complete reinstall of the entire system if i want to replace Xen 2.0.7 with Xen 3.0 if it becomes stable. So i''d rather go with the first option. But, otoh, my primary objective is to have a STABLE system. So what should i do? Kind regards, Robin van Leeuwen _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Robin van Leeuwen
2005-Aug-31 20:02 UTC
[Xen-users] Question about stability 32bit chroot and xen 2.0.7
I want to run a stable system with Xen, so my best choice is the xen-2.0.7 installation. I have however a AMD opteron which is 64 bit. Will i be able to run a stable Xen server in a 32 bit chroot enviroment on Debian 3.1 amd64 stable? Or would my best bet be, install Debian i386 on my amd64 and run xen-2.0.7 from there. The last option however needs a complete reinstall of the entire system if i want to replace Xen 2.0.7 with Xen 3.0 if it becomes stable. So i''d rather go with the first option. But, otoh, my primary objective is to have a STABLE system. So what should i do? Kind regards, Robin van Leeuwen _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Daniel Hulme
2005-Aug-31 21:46 UTC
Re: [Xen-users] Question about stability 32bit chroot and xen 2.0.7
> Will i be able to run a stable Xen server in a 32 bit chroot > enviroment on Debian 3.1 amd64 stable?I think you are confused about what Xen does. Xen is a hypervisor: it goes between the kernel and the hardware. You can''t run Xen "on" Debian; you might run a Debian guest on Xen though. Xen can''t run in a chroot environment because Xen itself does not care about filesystems and such high level things: it cares about letting the guest operating systems use the hardware in a safe way (FSVO safe). You can''t run dom0 in a chroot because there is nothing to set up the chroot environment for it: Xen boots it just as a normal bootloader would. Similarly, you wouldn''t want to run a domU in a chroot because the domain already gets its own filesystem. Of course, in both cases you can run *applications* in a chroot just as you would on a native Linux (or NetBSD or FreeBSD) system. To answer what you actually want to do rather than what you asked, Xen does not support mixing 32-bit and 64-bit guests. Either Xen and all guest operating systems are 64-bit, or they are all 32-bit. The same applies to PAE/non-PAE. This support is planned, but not for some time yet.> The last option however needs a complete reinstall of the > entire system if i want to replace Xen 2.0.7 with Xen 3.0 > if it becomes stable. So i''d rather go with the first option.> But, otoh, my primary objective is to have a STABLE system. > So what should i do?It depends on whether you want a stable system right now. The unstable tree (with PAE and 64-bit support) is expected to go into testing Real Soon Now, and once it does and the number of people trying it out increases, a stable 3.0 release should follow. If you can''t wait that long, go with 2.0.7 and 32-bit for now, and be ready to upgrade once you are happy with the stability. If changing your arch and reinstalling the packages is that much of a headache for you, consider changing your backup and installation procedure. On production systems, it is generally a good idea to set things up so if the system goes down with all hands you can install an identical replacement and restore backed-up data onto it with minimal administrator interaction. Of course, I appreciate that it isn''t always as easy as this... -- "And what if I assign a hundred programmers to it?" The master programmer shrugged. "Then the design will never be completed," he said. http://www.google.com/search?q=%22pgp+singing%22 <-- childish but funny http://surreal.istic.org/ <-- It''s like a DEATH CIRCUS! | keyid 885b170d _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Robin van Leeuwen
2005-Sep-01 09:05 UTC
[Xen-devel] Re: [Xen-users] Question about stability 32bit chroot and xen 2.0.7
Daniel Hulme wrote:>>Will i be able to run a stable Xen server in a 32 bit chroot >>enviroment on Debian 3.1 amd64 stable? >> >> >I think you are confused about what Xen does. Xen is a hypervisor: it >goes between the kernel and the hardware. You can''t run Xen "on" Debian; >you might run a Debian guest on Xen though. Xen can''t run in a chroot >environment because Xen itself does not care about filesystems and such >high level things: it cares about letting the guest operating systems >use the hardware in a safe way (FSVO safe). > >i''m familiar enough with xen and it''s internals, currently i''m setup 32bit servers, and 64 bit servers with errors, submitting my bugreports etc, helping out where i can.>You can''t run dom0 in a chroot because there is nothing to set up the >chroot environment for it: Xen boots it just as a normal bootloader >would. Similarly, you wouldn''t want to run a domU in a chroot because >the domain already gets its own filesystem. Of course, in both cases you >can run *applications* in a chroot just as you would on a native Linux >(or NetBSD or FreeBSD) system. > >I can compile xen 3.0 to boot DomU in 64 bit mode. and set Linux-2.6-xenU to architecture x86 instead of x86_64? Question is if i can boot with the xen3 kernel 64 bit and the domU xen32 bit. That''s not possible as i understand from your answer. My solution, could work, indeed you don''t need a chroot, but you should just setup your domU partitions with a x86 release of linux. But your stuck with a unstable kernel in that way. To answer what you actually want to do rather than what you asked, Xen>does not support mixing 32-bit and 64-bit guests. Either Xen and all >guest operating systems are 64-bit, or they are all 32-bit. The same >applies to PAE/non-PAE. This support is planned, but not for some time >yet. >So for now my only option is to install the whole thing 32 bit, debian + xen. tnx _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Robin van Leeuwen
2005-Sep-01 09:06 UTC
Re: [Xen-users] Question about stability 32bit chroot and xen 2.0.7
Daniel Hulme wrote:>>Will i be able to run a stable Xen server in a 32 bit chroot >>enviroment on Debian 3.1 amd64 stable? >> >> >I think you are confused about what Xen does. Xen is a hypervisor: it >goes between the kernel and the hardware. You can''t run Xen "on" Debian; >you might run a Debian guest on Xen though. Xen can''t run in a chroot >environment because Xen itself does not care about filesystems and such >high level things: it cares about letting the guest operating systems >use the hardware in a safe way (FSVO safe). > >i''m familiar enough with xen and it''s internals, currently i''m setup 32bit servers, and 64 bit servers with errors, submitting my bugreports etc, helping out where i can.>You can''t run dom0 in a chroot because there is nothing to set up the >chroot environment for it: Xen boots it just as a normal bootloader >would. Similarly, you wouldn''t want to run a domU in a chroot because >the domain already gets its own filesystem. Of course, in both cases you >can run *applications* in a chroot just as you would on a native Linux >(or NetBSD or FreeBSD) system. > >I can compile xen 3.0 to boot DomU in 64 bit mode. and set Linux-2.6-xenU to architecture x86 instead of x86_64? Question is if i can boot with the xen3 kernel 64 bit and the domU xen32 bit. That''s not possible as i understand from your answer. My solution, could work, indeed you don''t need a chroot, but you should just setup your domU partitions with a x86 release of linux. But your stuck with a unstable kernel in that way. To answer what you actually want to do rather than what you asked, Xen>does not support mixing 32-bit and 64-bit guests. Either Xen and all >guest operating systems are 64-bit, or they are all 32-bit. The same >applies to PAE/non-PAE. This support is planned, but not for some time >yet. >So for now my only option is to install the whole thing 32 bit, debian + xen. tnx _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Ian Pratt
2005-Sep-01 18:19 UTC
RE: [Xen-users] Question about stability 32bit chroot and xen 2.0.7
> I can compile xen 3.0 to boot DomU in 64 bit mode. > and set Linux-2.6-xenU to architecture x86 instead of x86_64? > Question is if i can boot with the xen3 kernel > 64 bit and the domU xen32 bit. That''s not possible as i > understand from your answer. > > My solution, could work, indeed you don''t need a chroot, but > you should just setup your domU partitions with a > x86 release of linux. But your stuck with a unstable kernel > in that way.Running a 64b guest kernel on a 32b file system works just fine. "uname -a" reports x86_64, but other than that you wouldn''t know the difference. Ian _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Robin van Leeuwen
2005-Sep-01 21:32 UTC
Re: [Xen-users] Question about stability 32bit chroot and xen 2.0.7
Ian Pratt wrote:>>I can compile xen 3.0 to boot DomU in 64 bit mode. >>and set Linux-2.6-xenU to architecture x86 instead of x86_64? >>Question is if i can boot with the xen3 kernel >>64 bit and the domU xen32 bit. That''s not possible as i >>understand from your answer. >> >>My solution, could work, indeed you don''t need a chroot, but >>you should just setup your domU partitions with a >>x86 release of linux. But your stuck with a unstable kernel >>in that way. >> >> > >Running a 64b guest kernel on a 32b file system works just fine. "uname >-a" reports x86_64, but other than that you wouldn''t know the >difference. > >Ian > >But i want it the other way around. I want to run a stable 64 bit server (debian-amd64 stable) with a stable xen (2.0.7) but, 2.0.7 doesn''t support 64 bit''s. Is there a way i still can use 2.0.7 AND make use of debian-amd64-stable. There is another catch (maybe an advantage) I have to recompile it myself to change some kernel-config settings and recompile at least the kernels. Can this be done? kind regards, Robin van Leeuwen _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Petersson, Mats
2005-Sep-02 09:12 UTC
RE: [Xen-users] Question about stability 32bit chroot and xen 2.0.7
> But i want it the other way around. I want to run a stable 64 > bit server > (debian-amd64 stable) with a stable xen (2.0.7) but, 2.0.7 > doesn''t support 64 bit''s. Is there a way i still can use > 2.0.7 AND make use of debian-amd64-stable.There is no way you can run a 64-bit OS on top of a 32-bit hypervisor, stable, unstable or otherwise. The reason, primarily, is that the hypervisor has to understand entire processor architecture, and AMD64 has 8 more gp registers than the 32-bit x86 architecture. These registers are not accessible in 32-bit mode, so you would end up with unsaved registers. Since some of these registers are of the type that doesn''t automatically get saved by the OS or C calling convention (ABI), they absolutely need to be saved and restored with Xen''s context switches. So you need a Xen hypervisor that understands 64-bit processors, or you have to run a 32-bit OS. [Aside from that, amd64 also uses 4 level page tables in combination with PAE mode, none of which I believe are supported in 2.0.x].> > There is another catch (maybe an advantage) I have to > recompile it myself to change some kernel-config settings and > recompile at least the kernels. > > Can this be done?No. -- Mats> > kind regards, > > Robin van Leeuwen > > > > > _______________________________________________ > 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