Chapter 4. Converting virtual machines to run on Red Hat Enterprise Virtualization

Warning

The Red Hat Enterprise Linux 6 version of the virt-v2v utility has been deprecated. Users of Red Hat Enterprise Linux 6 are advised to create a Red Hat Enterprise 7 virtual machine, and install virt-v2v in that virtual machine. The Red Hat Enterprise Linux 7 version is fully supported and documented in virt-v2v Knowledgebase articles.
virt-v2v can convert virtual machines to run on Red Hat Enterprise Virtualization. Virtual machines can be converted from Xen, KVM and VMware ESX / ESX(i) environments. Before converting virtual machines to run on Red Hat Enterprise Virtualization, you must attach an export storage domain to the Red Hat Enterprise Virtualization data center being used. Section 4.2, “Attaching an export storage domain” explains the process of attaching an export storage domain. For more information on export storage domains, see the Red Hat Enterprise Virtualization Administration Guide.

4.1. Acceptable converted storage output formats

It is important to note that when converting a guest virtual machine to run on Red Hat Enterprise Virtualization, not all combinations of storage format and allocation policy are supported. The supported combinations differ according to whether the Red Hat Enterprise Virtualization data center the guest will be imported into uses block (FC or iSCSI) or file (NFS) for its data storage domain. Note that virt-v2v writes to an export storage domain, and this is always required to be NFS.

Note

The important element for a successful virtual machine import into Red Hat Enterprise Virtualization is the type of the data domain. virt-v2v is unable to detect the data center type, so this check must be applied manually by the user.

Table 4.1. Allocation Policy: Preallocated

Data Domain Type Storage Format Supported
NFS raw Yes
qcow2 No
FC/iSCSI raw Yes
qcow2 No

Table 4.2. Allocation Policy: Sparse

Data Domain Type Storage Format Supported
NFS raw Yes
qcow2 Yes
FC/iSCSI raw No
qcow2 Yes
Data format and allocation policy of the virtual machine being converted by virt-v2v will be preserved unless the output data format and allocation policy are specified using the -of and -oa parameters respectively. To import virtual machines using sparse allocation into an FC or iSCSI data center, the storage format must be converted to qcow2. This is achieved by passing the parameters -of qcow2 -oa sparse to virt-v2v. Note that converting between raw and qcow2 formats is a resource intensive operation, and roughly doubles the length of time taken for the conversion process.

Important

Preallocated qcow2 storage is never supported in Red Hat Enterprise Virtualization, although virt-v2v is able to write it. Import to Red Hat Enterprise Virtualization will fail.