Migration of a physical machine to a RHEV environment is performed in two steps. First, you create an image of the machine in a .tib file on an intermediate storage. Next, you deploy this image to a new or existing RHEV virtual machine. Acronis Backup can create a new, fully configured virtual machine directly in a RHEV export domain. You only need to import it to the required data center.
A machine image is also referred to as a "backup" because it is created using the backup software.
When choosing the migration method, take into account the following considerations.
Decide where you will save the image. With the default level of data compression, the required storage space is around 70% of the amount of data to be migrated. Consider an SMB (CIFS) or NFS network share or a fixed disk of the machine being migrated. External devices, such as USB drives, are also supported.
If there is a storage connected to the machine using iSCSI HBA, exclude it from the image. You will be able to add this storage to the resulting virtual machine using iSCSI software initiator after the migration completes.
A Fibre Channel-connected storage cannot be added to a RHEV virtual machine. If you need the storage on the resulting virtual machine, let it be included in the image. The storage will be converted to a virtual disk. Otherwise, exclude the storage from the image.
The image can be taken under the operating system (hot imaging) or under bootable media (cold imaging). Take into account the following considerations.
Is the server reboot/downtime acceptable?
During cold imaging, the imaged machine will be off-line and will not provide the necessary services.
Do you need Acronis software on the resulting machine?
Hot imaging requires installation of an Acronis agent on the physical machine. The agent will be present in the migrated system as well. If you are planning to back it up using Acronis Backup, having the agent already installed is a plus. If adding software to the system is not acceptable, use cold imaging.
Do you need migration on a schedule?
A migration that uses hot imaging can be scheduled. This comes in handy for updating the virtual "standby" server. Cold migration is performed interactively.
Is it critical that the latest changes to the original system will be missing in the migrated system?
Once the hot imaging starts, Acronis Backup takes a snapshot of the physical machine. Then, it compresses the snapshot data and saves it to the location you specify. During this process, changes to the original system may occur. The changes will not be transferred to the migrated system because they are not present in the snapshot. If you decommission the physical machine or return it to a lessor, the changes will be lost. To avoid the data loss, use cold imaging.
Acronis Backup can deploy the image automatically as soon as it is created. This method is called "conversion to a virtual machine". The resulting virtual machine will be similar to the original machine. If you configure the deployment as a separate operation (recovery), you will be able to change the machine configuration: add/remove/resize disks, and set the virtual machine memory.
Resizing the disks during recovery makes good sense because the newly created disks always have the Raw format. They will needlessly occupy a lot of space if the data size is much less than the disk size. The alternative way to save space is recovery to a previously created virtual machine with the optimal disk sizes.
Recreate logical volumes or convert them to basic ones?
A machine created by Acronis always has basic volumes. If logical volumes or MD devices are present in the image, they will be converted to basic ones. The same applies to dynamic volumes used in Windows systems. The operating system remains bootable, since Acronis properly updates GRUB and standard Windows loaders. Custom boot loaders may require manual reactivation.
The original LVM structure can be reproduced only if you create the RHEV virtual machine in advance and boot it using bootable media. Then, either perform recovery with the enabled Apply RAID/LVM option, or create the LVM structure manually and then perform recovery with the disabled option.
There is no option to recreate dynamic volumes during recovery. If you need dynamic volumes on the resulting machine, create the volume group using the disk management functionality of the bootable media. Then, perform recovery over these volumes.
Are you ready to provide necessary drivers for Universal Restore?
When Acronis creates a virtual machine on its own and deploys an image to it, the necessary drivers are installed automatically because the software knows what drivers or modules are required for the machine. When you create a machine and boot it using bootable media, Acronis treats it as a physical machine. This is why you need to explicitly apply Universal Restore and specify the path to the necessary drivers. The ISO of the floppy disk with the drivers can be found in the RHEV ISO domain. Its default name is virtio*.iso.
Choose intermediate storage