Backing Up Virtual Machines

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Imaging method: hot or cold?
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.
Deployment method: convert or recover?
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.
Let Acronis create a virtual machine or do it yourself?
Take into account the following considerations.
 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.