Worst error message ever?
This gem from Xen is the most obtuse, unhelpful error message I’ve seen in quite a while:
Error: Device 768 (vbd) could not be connected. Hotplug scripts not working.
One of the top Google results for this text is a PDF file of the official Xen 3.1 Release Notes. According to these notes, you should check whether your CPU load is abnormally high, and configure Xen such that the host domain (dom0) is assigned fewer CPU cores.
When that didn’t work, I continued Googling. It turns out that this is the error message produced by Xen when you configure a guest OS image to use a non-existent device (block device, LVM logical volume, loopback file, etc.) as a virtual disk.
Compare the aforementioned error message to the following suggestion:
Error: invalid device /dev/vg0/blah specified in /etc/xen/foo.cfg, line X.
I guess that would have been far too easy.
thanks for this post. i join you in shouting bad words at people creating error messages like this one.
lars
5 Jun 08 at 3:52 am
Hi,
this blog entry just saved the longer part of my night. It’s not fair that a kernel update leads to the /dev/sdX devices being reordered… Now I changed the device names into /dev/disk/by-id/… to be save from such surprises…
Thanks, Dirk
Dirk Hillbrecht
30 Sep 08 at 6:49 pm
I can confirm this.
The thing i overlooked in my xen config was the use of /dev/loop/0 instead of /dev/loop0 :-/
Mark
29 Oct 08 at 6:36 am