On Thu, Jun 22, 2006 at 05:07:55PM -0600, Tillman Hodgson wrote:
> When attempting to start up my 5th DomU, I run into an error:
> 
> [root@minerva ~]$ xm create -c /usr/pkg/etc/xen/domU.www
> Using config file "/usr/pkg/etc/xen/domU.www".
> Error: Adding extent to vbd failed: device (vbd (uname file:/virtual/www.img) (dev wd0d) (mode w)), error 8
> 
> [root@minerva ~]$ tail -1 /var/log/messages
> Jun 22 17:02:41 minerva /netbsd: xbdback VBD grow domain 14: unknwon device 0x2c890
> 
> (yes, "unknown" has a spelling mistake in the log)
> 
> To create the DomU, I merely copied my standard NetBSD image file to a
> new file (all the DomUs run a version of the  same image file though
> each is customized for IP address, etc) and created a new config file:
> 
> kernel = "/netbsd-XENU"
> memory = 64
> name = "www"
> cpu = -1
> nics = 0
> disk = [ 'file:/virtual/www.img,wd0d,w' ]
> root = "/dev/wd0d"
> 
> /virtual/www.img exists and has the same md5 as my original "barebones"
> image file.
> 
> It almost seems like I've run out of virtual devices, but it looks to me
> like there's 64 of them in /dev.
> 
> Any pointers on where I should look to troubleshoot this?

Use vnconfig -l to find the first unused vnd (I guess only vnd0-3 are used
as you have 4 running domains) and then try to configure it by hand:
vnconfig vnd4 /virtual/www.img

If it fails, the problem is here. It's possible you're hitting the in-kernel
limit; if so rebuild a kernel with more vnd, or use one from a recent netbsd-3
snapshot.

-- 
Manuel Bouyer <bouyer@antioche.eu.org>
     NetBSD: 26 ans d'experience feront toujours la difference
--