I got an error yesterday when trying to create a xen virtual machine with a lot of disks.
I had to add 32 disks on the machine, which would be used to backup the hard drives.
The error was Unable to find number for device (sdq1). I had devices up to sdab1, but he already stuck at the sdq1.
How to work around this problem you ask? Really easy it seems: Just use other device "types" for the disks beginning at sdq1. So sdq1 became hda1.
And all went well.
Viva Xen!!