[CentOS-virt] xm attach-block reboots entire server

[Steve Campbell]

I'm still trying to get xen working before Centos 6 and KVM just for 
experience. I seem to be able to do most of what I what with VMs, but 
I've run into another problem with CD/DVDs.

I can get a DVD mounted on the host domain just fine, but when I try and 
attach-block to a running guest VM, the entire server reboots. I've 
tried many different commands versions based on what Google finds, but 
I'm not getting anywhere. I end up using scp to copy the data from the 
host to the guest.

The guest is basically defined as a full virtualized domain. I'm using 
/dev/scd0 as the device (it's listed on the mount command) as both 
frontend and backend devices. And I've tried a few other devices as 
well, but the same result.

Anyone know of a reason or fix, please?

steve campbell