MD devices, known as Linux Software RAID, combine several volumes and make solid block devices (/dev/md0, /dev/md1, ..., /dev/md31). The information about MD devices is stored in /etc/raidtab or in dedicated areas of those volumes.
You can back up active (mounted) MD devices in the same way as logical volumes. The MD devices appear at the end of the list of volumes available for backup. If you select MD devices for backup, the structure of the MD devices will be backed up along with their contents.
Backing up volumes included in MD devices does not make sense when an MD device is mounted, as it won’t be possible to recover them.
When recovering MD devices under bootable media, the structure of MD devices can be recreated automatically. For detailed information about recovering MD devices under bootable media, see Recovering MD devices and logical volumes.
For information about assembling MD devices when performing recovery in Linux, see Assembling MD devices for recovery (Linux).