About the supported virtual disk formats and disk provisioning during VM recovery
Red Hat Virtualization supports the following allocation methods for virtual disks:
Pre-allocated (Thick provision)
Pre-allocated indicates fully-allocated raw disks.
Thin provision
Thin provisioned disks are of the following types:
Raw sparse (default on file storage such as NFS)
QCOW2 (default on block storage such as FC, SAN, iSCSI)
The thin provisioned virtual disk that is created on block storage is always in QCoW2 format.
Based on the disk provisioning option that you select in NetBackup, the virtual disks are created as described in the following table:
Table: Virtual disk provisioning for Red Hat Virtualization VM recovery
The disk provisioning option that is selected during restore | Original disk format during backup | ||
|---|---|---|---|
RAW sparse | RAW pre-allocated | QCOW2 | |
Original or default | RAW sparse (QCOW2 on block storage) | RAW pre-allocated | RAW sparse (QCOW2 on block storage) |
Thin | RAW sparse (QCOW2 on block storage) | RAW sparse (QCOW2 on block storage) | RAW sparse (QCOW2 on block storage) |
Thick | RAW pre-allocated | RAW pre-allocated | RAW pre-allocated |
VM templates can have the disks that have RAW or QCOW2 format.
Storage allocation can be thin (dependent) or clone (independent).
In Clone (independent) allocation, the contents of template disks are copied to the VM disk.
In Thin (dependent) allocation, the template disks are referred as base disks for the VM.
When multiple VMs are deployed from the same template with Thin allocation, then the VMs share the template disks.