ACRONIS Backup & Recovery 11 Guide de l'utilisateur télécharger pdf (Page 37)

For detailed instructions on how to recover logical volumes, see Recovering MD devices and logical

volumes (p. 38).

3.5.2.2 Backing up MD devices

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

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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 (p. 38).

For information about assembling MD devices when performing recovery in Linux, see Assembling

MD devices for recovery (Linux) (p. 37).

3.5.2.3 Backing up hardware RAID arrays (Linux)

Hardware RAID arrays under Linux combine several physical drives to create a single partitionable

disk. The special file related to a hardware RAID array is usually located in /dev/ataraid. You can back

up hardware RAID arrays in the same way as ordinary hard disks.

Physical drives that are part of hardware RAID arrays may be listed alongside other disks as if they

had a bad partition table or no partition table at all. Backing up such disks does not make sense as it

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3.5.2.4 Assembling MD devices for recovery (Linux)

In Linux, when performing recovery from a disk backup to an existing MD device (also called Linux

Software RAID), make sure that this device is assembled at the time of recovery.

If the device is not assembled, assemble it by using the mdadm utility. Here are two examples:

Example 1. The following command assembles the device /dev/md0 combined from the volumes

/dev/sdb1 and /dev/sdc1:

mdadm --assemble /dev/md0 -ayes /dev/sdb1 /sdc1

Example 2. The following command assembles the device /dev/md0 combined from the disks

/dev/sdb and /dev/sdc:

mdadm --assemble /dev/md0 -ayes /dev/sdb /dev/sdc

If the recovery requires the machine to be rebooted (usually, when the volumes to recover include

the boot partition), follow these guidelines:

 If all parts of the MD device are volumes (a typical case, such as in the first example), make sure

that each volume typecalled partition type or system IDis Linux raid automount; the

hexadecimal code of this partition type is 0xFD. This will guarantee that the device will be

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