Live storage migration with thin luns at the back and preallocated disks at RHEV is possible.
My Knowlede on this is limited and as such, you need to tell me more about what you want to achieve.
But per this documentation, it seems not possible but I could be wrong and you need to really give us a full scenario.
Consider the following when using live storage migration:
- Live storage migration creates a snapshot.
- You can live migrate multiple disks at one time.
- Multiple disks for the same virtual machine can reside across more than one storage domain, but the image chain for each disk must reside on a single storage domain.
- You can live migrate disks only between two file-based domains (NFS, POSIX, and GlusterFS) or between two block-based domains (FCP and iSCSI).
- You cannot live migrate direct LUN hard disk images or disks marked as shareable.
Hope this helps.