Re: [Xen-users] Error: Device 2049 (vbd) could not be connected. Backend device not found.

[Abi Chirayil <abi@xxxxxxxxxxxxxx>]

Joe Warren-Meeks wrote:

>
> On 27 Apr 2006, at 14:43, Joe Warren-Meeks wrote:
>
> Hey guys,
>
>>> I've installed xen 3 and xen-tools on my ubuntu server and all seems
>>> well, until I try to start a client domain. (running on Linux
>>> xenserver 2.6.12.6-xen #1 SMP Wed Feb 1 21:23:17 UTC 2006 i686
>>> GNU/Linux)
>>
>>
>> Bit of a follow-up. If I try to start the DomU, it initally errors as
>> so:
>>
>> root@xenserver:/etc/xen# xm create -c squid1.cfg
>> Using config file "squid1.cfg".
>> Error: Device 2049 (vbd) could not be connected. Backend device not
>> found.
>>
>> and then shows up as paused in 'xm list'
>>
>> If I then attach a console to it, then unpause I see the following
>> error at the end:
>>
>> VFS: Cannot open root device "sda1" or unknown-block(0,0)
>> Please append a correct "root=" boot option
>> Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-
>> block(0,0)
>>
>> I've tried adding /dev/ nodes using MAKEDEV in both the Dom0 and DomU
>> and tried changing sda to hda, to no avail.
>>
>> Anyone got a pointer to where I can start looking?
>
>
> As a futher follow up, if I use xen-create-image to create a new domU,
> this completes fine and then starts the image successfully! I can then
> go and start all the other images and all is fine.
>
> Once I've halted them all and rebooted the server itself, it all stops
> working again.
>
> Anyone got any pointers? This is getting quite frustrating.
>
I'm getting exactly the same error (also using Ubuntu). I just tried
mounting and unmounting the one of the images and that seems to get
everything working - till the next reboot.

mount -o loop /vserver/images/vmNMS.img /vserver/vm_base/
umount /vserver/vm_base/

Any idea why this happens? I've also been pulling my hair out the past
couple of days.

Regards,
Abi





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