[ovirt-users] Disk Allocation policy changes after a snapshot

Hi I have linux VM with 2 disks one for OS is sparse the other is for a Database and is Preallocated. When I take a snapshot of the VM both disks change to sparse policy but the disks in the snapshot are 1 sparse and 1 allocated. Before the snapshot the VM was running fine, now it crashes when data is written to the database. When I delete the snapshot the disks go back to 1 sparse and 1 allocated. Has anyone else seen this happen. Ovirt is 4.3.2.1-1.el7 and it is running on a hostedEngine Many thanks Kevin