Cloned from launchpad blueprint https://blueprints.launchpad.net/nova/+spec/resize-down-consistency.

Description:

Currently, almost all of the hypervisor which can't safely resize the disk from bigger size to small size just ignore it, either compare the old size and newer size then just pick the bigger one or just log it, for both case it would be a problem since the flavor of the instance changed, but the disk size doesn't, for now just hyperv and xen verify it and thow a exception, for other hypervisor we need to deal with it in the same way.

Specification URL (additional information):

None