Re: domcreate_launch_dm: unable to add disk devices

[smj%ma.sdf.org@localhost]

> On Thu, Apr 28, 2016 at 07:30:27AM +0000, smj%ma.sdf.org@localhost wrote:
> > [...]
> > libxl: error: libxl_device.c:875:device_backend_callback: unable to connect device with path /local/domain/0/backend/vbd/87/51712
> > libxl: error: libxl_device.c:875:device_backend_callback: unable to connect device with path /local/domain/0/backend/vbd/87/51728
> > libxl: error: libxl_create.c:951:domcreate_launch_dm: unable to add disk devices
> > libxl: error: libxl_dm.c:1269:libxl__destroy_device_model: could not find device-model's pid for dom 87
> > libxl: error: libxl.c:1419:libxl__destroy_domid: libxl__destroy_device_model failed for 87
> > libxl: error: libxl_device.c:875:device_backend_callback: unable to disconnect device with path /local/domain/0/backend/vbd/87/51712
> > libxl: error: libxl_device.c:875:device_backend_callback: unable to disconnect device with path /local/domain/0/backend/vbd/87/51728
> > libxl: error: libxl.c:1455:devices_destroy_cb: libxl__devices_destroy failed for 87
> 
> You will have to find if the block script is called, and if so why it is
> failing.

So I've tried 4.1, 4.2 and 4.5  Always building the appropriate xentools and
I can only run DOMUs for about a day before block ceases to be called.  
Restarting xencommons does not resolve the issue, I have to reboot.  I did
fix one issue in /usr/pkg/etc/xen/scripts/vif-bridge where bridge0 would be
used for about half a day and then suddenly it would switch to xen-br0 and
fail (I never used xen-br0).  I repalced #xbridge=$(xenstore-read "$xpath/bridge")
with xbridge=bridge0 and that continues to allow it to work.  However, it
will continue to work until /usr/pkg/etc/xen/script/block ceases to be 
called and I'm not exactly sure what store is being corrupt.  I do have a
set -x in block, so I can see when it is called when things are working.
I also have xenstore trace running and while It generates a lot of output, 
there really is no useful information into exactly what is happening.

I've rebooted the machine again and domu's happily get created and start up.

Are there any sysctl settings I should be tuning?