Created attachment 1224431 [details]
engine.log

Description of problem:
Creation of a VM pool fails when the used template has a RAW disk. With QCOW2 disk(s) it works fine.
The event log also contains contradictory messages.

Version-Release number of selected component (if applicable):
rhevm-4.0.6-0.1.el7ev.noarch

How reproducible:
always

Steps to Reproduce:
1. In webadmin, create a VM with 1 disk (1GB, VirtIO, Thin Provision).
2. Create new template from the VM. Make sure to set the disk format to 'Raw'.
3. Create new VM pool from the template.
   (Number of VMs & VMs per user: 10, Prestarted: 0)

Actual results:
The VM pool is not created. The event log shows following contradictory messages:
-~-
6:17:47 PM Not all VMs where successfully created in VM Pool <UNKNOWN>.
6:17:48 PM Failed to create VM Pool pool-raw (User: admin@internal-authz).
6:17:49 PM VM Pool pool-raw (containing 10 VMs) was created by admin@internal-authz.
-~-

engine.log contains this message (find the full log attached):
18:17:47,279 WARN  [org.ovirt.engine.core.bll.AddVmCommand] (org.ovirt.thread.pool-6-thread-8) [4f77fb97] Validation of action 'AddVm' failed for user admin@internal-authz. Reasons: VAR__ACTION__ADD,VAR__TYPE__VM,ACTION_TYPE_FAILED_THIN_TEMPLATE_DISKS_SHOULD_ONLY_BE_COW


Expected results:
The VM pool is successfully created.

Additional info:
Regression against rhevm-3.6.10-0.1.el6.noarch
Reproduced also in ovirt-engine-4.1.0-0.0.master.20161124091617.git2785371.el7.centos.noarch