2.5. Placement of LVM-VDO in the storage stack
You must place certain storage layers under a VDO logical volume and others on top of it.
You can place thick-provisioned layers on top of VDO, but you cannot rely on the guarantees of thick provisioning in that case. Since the VDO layer is thin-provisioned, the effects of thin provisioning apply to all layers. If you do not monitor the VDO volume, you might run out of physical space on thick-provisioned volumes on top of VDO.
Since the supported placement of the following layers is under VDO, do not place them on top of VDO:
- DM Multipath
- DM Crypt
- Software RAID (LVM or MD RAID)
The following configurations are not supported:
- VDO on top of a loopback device
- Encrypted volumes on top of VDO
- Partitions on a VDO volume
- RAID, such as LVM RAID, MD RAID, or any other type, on top of a VDO volume
- Deploying Ceph Storage on LVM-VDO