Stephan Augustin
2006-Jan-30 14:55 UTC
[Xen-users] Error: Device 769 (vbd) could not be connected. Backend device not found.
Hi, I have installed debian 3.1 on an Intel Pentium D processor 920 ( including vanderpool.) The installation worked fine and i''m able to start guest-domains. When I try to start the 5.th Guest-Domain, I Get the following error: Error: Device 769 (vbd) could not be connected. Backend device not found. this problem exists still if i have shutdown or destroyed all guests, after this I can start 4 guests again. could someone help me ? thank you stephan -- Stephan Augustin Rosenpark 3 65795 Hattersheim 06190/9355448 0173/1735867 _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Molle Bestefich
2006-Jan-30 18:53 UTC
Re: [Xen-users] Error: Device 769 (vbd) could not be connected. Backend device not found.
Stephan Augustin wrote:> When I try to start the 5.th Guest-Domain, I Get the following error: > > Error: Device 769 (vbd) could not be connected. Backend device not found.Seems a lot of people are having this problem. Should be in the FAQ, and the error message should be clearer. I have no clue where or how to fix the error message, however. I can take a wild guess at why you might be seeing it though - have you run out of loop devices in dom0? HTH _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Tony Clark
2006-Jan-30 20:01 UTC
Re: [Xen-users] Error: Device 769 (vbd) could not be connected. Backend device not found.
I also see this with the disks mounted as LVM partitions and not using loopbacks. It happens for me off the first or second DomU instance, seemingly at random. Sorry I have no info on a fix though; just thought I''d feed in my experience that''s not related to loopback devices. Tony On 31/01/2006, at 5:23 AM, Molle Bestefich wrote:> Stephan Augustin wrote: >> When I try to start the 5.th Guest-Domain, I Get the following error: >> >> Error: Device 769 (vbd) could not be connected. Backend device not >> found. > > Seems a lot of people are having this problem. > Should be in the FAQ, and the error message should be clearer. > > I have no clue where or how to fix the error message, however. > > I can take a wild guess at why you might be seeing it though - have > you run out of loop devices in dom0? > > HTH > > _______________________________________________ > Xen-users mailing list > Xen-users@lists.xensource.com > http://lists.xensource.com/xen-users >tony clark director - tony.clark@rsp.com.au --------------------------------------------------------------- rising sun pictures - www.rsp.com.au redefining visual effects delivery --------------------------------------------------------------- address level 1 / 133 gouger street adelaide south australia 5000 --------------------------------------------------------------- adelaide ph +61 8 8400 6400 fax +61 8 8400 6401 sydney ph +61 2 9338 6400 fax +61 2 9338 6401 --------------------------------------------------------------- rising sun research - http://research.rsp.com.au --------------------------------------------------------------- _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Stephan Augustin
2006-Jan-30 21:50 UTC
Re: [Xen-users] Error: Device 769 (vbd) could not be connected. Backend device not found.
Hi, I tried some times again, and now i am running 7 machines concurrent. during installation, the same error occured, but this was because i hadn''t mounted the image-file partition at this time. the only difference i can see is that i now didnt use the dom0_mem=64000 parameter in the grub/menu.lst config. perhaps it was this , I dont know. if someone knows more about, please tell me thank you for your fast help stephan Am Montag, 30. Januar 2006 21:01 schrieb Tony Clark:> I also see this with the disks mounted as LVM partitions and not using > loopbacks. It happens for me off the first or second DomU instance, > seemingly at random. > > Sorry I have no info on a fix though; just thought I''d feed in my > experience that''s not related to loopback devices. > > Tony > > On 31/01/2006, at 5:23 AM, Molle Bestefich wrote: > > Stephan Augustin wrote: > >> When I try to start the 5.th Guest-Domain, I Get the following error: > >> > >> Error: Device 769 (vbd) could not be connected. Backend device not > >> found. > > > > Seems a lot of people are having this problem. > > Should be in the FAQ, and the error message should be clearer. > > > > I have no clue where or how to fix the error message, however. > > > > I can take a wild guess at why you might be seeing it though - have > > you run out of loop devices in dom0? > > > > HTH > > > > _______________________________________________ > > Xen-users mailing list > > Xen-users@lists.xensource.com > > http://lists.xensource.com/xen-users > > tony clark > director - tony.clark@rsp.com.au > --------------------------------------------------------------- > rising sun pictures - www.rsp.com.au > redefining visual effects delivery > --------------------------------------------------------------- > address level 1 / 133 gouger street > adelaide south australia 5000 > --------------------------------------------------------------- > adelaide ph +61 8 8400 6400 fax +61 8 8400 6401 > sydney ph +61 2 9338 6400 fax +61 2 9338 6401 > --------------------------------------------------------------- > rising sun research - http://research.rsp.com.au > ----------------------------------------------------------------- Stephan Augustin Rosenpark 3 65795 Hattersheim 06190/9355448 0173/1735867 _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Stephan Augustin
2006-Jan-31 08:14 UTC
Re: [Xen-users] Error: Device 769 (vbd) could not be connected. Backend device not found.
I have figured out that if it happens all loop-devices are fully used. can i get more of them ? stephan Am Montag, 30. Januar 2006 21:01 schrieb Tony Clark:> I also see this with the disks mounted as LVM partitions and not using > loopbacks. It happens for me off the first or second DomU instance, > seemingly at random. > > Sorry I have no info on a fix though; just thought I''d feed in my > experience that''s not related to loopback devices. > > Tony > > On 31/01/2006, at 5:23 AM, Molle Bestefich wrote: > > Stephan Augustin wrote: > >> When I try to start the 5.th Guest-Domain, I Get the following error: > >> > >> Error: Device 769 (vbd) could not be connected. Backend device not > >> found. > > > > Seems a lot of people are having this problem. > > Should be in the FAQ, and the error message should be clearer. > > > > I have no clue where or how to fix the error message, however. > > > > I can take a wild guess at why you might be seeing it though - have > > you run out of loop devices in dom0? > > > > HTH > > > > _______________________________________________ > > Xen-users mailing list > > Xen-users@lists.xensource.com > > http://lists.xensource.com/xen-users > > tony clark > director - tony.clark@rsp.com.au > --------------------------------------------------------------- > rising sun pictures - www.rsp.com.au > redefining visual effects delivery > --------------------------------------------------------------- > address level 1 / 133 gouger street > adelaide south australia 5000 > --------------------------------------------------------------- > adelaide ph +61 8 8400 6400 fax +61 8 8400 6401 > sydney ph +61 2 9338 6400 fax +61 2 9338 6401 > --------------------------------------------------------------- > rising sun research - http://research.rsp.com.au > ----------------------------------------------------------------- Stephan Augustin Rosenpark 3 65795 Hattersheim 06190/9355448 0173/1735867 _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Michael Mey
2006-Jan-31 11:19 UTC
Re: [Xen-users] Error: Device 769 (vbd) could not be connected. Backend device not found.
On Tuesday 31 January 2006 09:14, Stephan Augustin wrote:> I have figured out that if it happens all loop-devices are fully used. can > i get more of them ?AFAIK you can set the number of loopback devices in your kernel config. Thus you have to recompile your xen-kernel. Michael -- ---------------------------------------------------------------------------------------- Michael Mey Thinking Objects Software GmbH | mailto: michael.mey@to.com Lilienthalstrasse 2/1 | phone: +49 711 88770-147 70825 Stuttgart-Korntal, Germany | fax: +49 711 88770-449 ---------------------------------------------------------------------------------------- _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Molle Bestefich
2006-Jan-31 12:32 UTC
Re: [Xen-users] Error: Device 769 (vbd) could not be connected. Backend device not found.
Michael Mey wrote:> Stephan Augustin wrote: > > I have figured out that if it happens all loop-devices are fully used. can > > i get more of them ? > > AFAIK you can set the number of loopback devices in your kernel config. Thus > you have to recompile your xen-kernel.That may be true, but it''s much easier to adjust it on the kernel command line. Just add max_loop=128 or some such. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Stephan Augustin
2006-Jan-31 12:42 UTC
Re: [Xen-users] Error: Device 769 (vbd) could not be connected. Backend device not found.
Am Dienstag, 31. Januar 2006 13:32 schrieb Molle Bestefich:> Michael Mey wrote: > > Stephan Augustin wrote: > > > I have figured out that if it happens all loop-devices are fully used. > > > can i get more of them ? > > > > AFAIK you can set the number of loopback devices in your kernel config. > > Thus you have to recompile your xen-kernel. > > That may be true, but it''s much easier to adjust it on the kernel command > line. Just add max_loop=128 or some such.Do you mean the commandline kernel /boot/xen.gz in /boot/grub/menu.lst ? stephan _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Molle Bestefich
2006-Jan-31 13:20 UTC
Re: [Xen-users] Error: Device 769 (vbd) could not be connected. Backend device not found.
Stephan Augustin wrote:> > That may be true, but it''s much easier to adjust it on the kernel command > > line. Just add max_loop=128 or some such. > > Do you mean the commandline > kernel /boot/xen.gz > in /boot/grub/menu.lst ?No, that''s the parameter line for the hypervisor. The loop devices exist within the domain 0 kernel. So you must append the max_loop parameter to the "module=<linux-dom0-kernel>" line in your grub configuration file. Sorry, should''ve mentioned that. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Stephan Augustin
2006-Jan-31 13:40 UTC
Re: [Xen-users] Error: Device 769 (vbd) could not be connected. Backend device not found.
Am Dienstag, 31. Januar 2006 14:20 schrieb Molle Bestefich:> Stephan Augustin wrote: > > > That may be true, but it''s much easier to adjust it on the kernel > > > command line. Just add max_loop=128 or some such. > > > > Do you mean the commandline > > kernel /boot/xen.gz > > in /boot/grub/menu.lst ? > > No, that''s the parameter line for the hypervisor. > The loop devices exist within the domain 0 kernel. > So you must append the max_loop parameter to the > "module=<linux-dom0-kernel>" line in your grub configuration file. > > Sorry, should''ve mentioned that.Sorry , but this doesnt work for me.. do I have to do something else for get this working ? i have this script : "If you have the “loop” driver compiled into your kernel, you need to add “max_loop=64” to your kernel boot arguments (the “append=” line in lilo.conf, or to the end of the “kernel” line in grub’s menu.lst), and reboot." If you have the “loop” driver compiled as a module, you need to insmod it with “max_loop=64” added to its options. On Debian systems, you edit /etc/modules.conf and add “options loop max_loop=64”, and “rmmod loop” “modprobe loop”. If you’re using devfs, then stop here. The new /dev/loop* will appear automatically. If not, you’ll need to edit and run MAKEDEV: Change: loop) for part in 0 1 2 3 4 5 6 7 do makedev loop$part b 7 $part $disk done ;; To: loop) for part in `seq 0 63` do makedev loop$part b 7 $part $disk done ;; And run “MAKEDEV loop”. " with the original debian -kernel, It is possible to use the modules - but this doesnt create more loop-devices. and even the kernel /boot/vmlinuz-2.6[...] max_loop=64 line does not work. under the xen-kernel the command-line doesnt work ( I dont get more devices) , and the modprobe command aborts with an error stephan _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Molle Bestefich
2006-Jan-31 13:52 UTC
Re: [Xen-users] Error: Device 769 (vbd) could not be connected. Backend device not found.
Stephan Augustin wrote: [...] Hrm, good info. In a more concise form it would be appropriate for a XEN FAQ, me thinks.> and even the > kernel /boot/vmlinuz-2.6[...] max_loop=64 > line does not work.Doesn''t look right either. Dom0 is loaded via the "module", not the "kernel" grub command.> under the xen-kernel the command-line doesnt work ( I dont get more devices) ,As in, "they do not appear in /dev" or "I''ve run ''mknod /dev/loop/123 b 7 123'' but I''m getting error messages when I use the device ? In case of the latter, which error messages?> and the modprobe command aborts with an errorProvide a better error description, please. The above doesn''t really get us anywhere. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Stephan Augustin
2006-Jan-31 14:34 UTC
Re: [Xen-users] Error: Device 769 (vbd) could not be connected. Backend device not found.
Am Dienstag, 31. Januar 2006 14:52 schrieb Molle Bestefich:> Stephan Augustin wrote: > [...] > Hrm, good info. > In a more concise form it would be appropriate for a XEN FAQ, me thinks. > > > and even the > > kernel /boot/vmlinuz-2.6[...] max_loop=64 > > line does not work. > > Doesn''t look right either. > Dom0 is loaded via the "module", not the "kernel" grub command.^^ this was the command line for the unmodified original debian kernel without xen, for showing that it dont works in original debian ( without xen ! )> > under the xen-kernel the command-line doesnt work ( I dont get more > > devices) , > As in, > "they do not appear in /dev" or > "I''ve run ''mknod /dev/loop/123 b 7 123'' but I''m getting error > messages when I use the device > ?I realised the ^^ snipped patch in the MAKEDEV file, which should create the loop-devices between 0 up to 63 during boot They do not appear in /dev I''ve run mknod /dev/loop8 b 7 8 but I didn''t get any error message vhost:~# losetup /dev/loop8 /dev/loop8: [f5d8]:-1 (l:� $) offset -1208435526, undefined encryption loop: can''t get info on device /dev/loop8: No such device or address now i run xm create debian.5 now it works :-? I dont know why... but why are these devices not createt automatically on boot ? but it Works - Thank you very much for your help stephan> In case of the latter, which error messages? > > > and the modprobe command aborts with an error > > Provide a better error description, please. > The above doesn''t really get us anywhere. > > _______________________________________________ > Xen-users mailing list > Xen-users@lists.xensource.com > http://lists.xensource.com/xen-users-- Stephan Augustin Rosenpark 3 65795 Hattersheim 06190/9355448 0173/1735867 _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Molle Bestefich
2006-Jan-31 14:38 UTC
Re: [Xen-users] Error: Device 769 (vbd) could not be connected. Backend device not found.
Stephan Augustin wrote:> but why are these devices not createt automatically on boot ?Depends on whether you are using a static /dev, devfs or udev.> but it Works - Thank you very much for your helpnp. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users