Content needs to be added to the Storage section of the Admin Guide that virtio-disk can change numbering after a resize but image disks can now be identified from within the guest by engine id. With this update, image disks are now identifiable from within the guest by engine id, for example, by looking under /dev/disk/by-id. The disk id is now passed to the guest as the disk serial.
*** Bug 1380483 has been marked as a duplicate of this bug. ***
Assigning to Avital for review. Avital, there is more information about the reasoning for this change in the duplicate bug 1380483.
Updated document: https://access.redhat.com/documentation/en-us/red_hat_virtualization/4.1/html-single/administration_guide/#Understanding_virtual_disks