46380: Acronis Cyber Protect, Acronis Backup for Linux: LVM Structure Cannot Be Partially Restored during Automatic Mapping

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Last update: 30-04-2021

This article details aspects of LVM backup and recovery with Acronis Cyber Protect, Acronis Cyber Backup and Acronis Backup 11.7/11.5

Description

Acronis products that support Linux systems for backup and recovery have a few particularities when working with logical volumes such as MD devices and LVM structures. 

When selecting logical volumes for backup, the entire logical volume structure will always be saved to the backup along with the volume data contents. This volume structure is kept as separate meta-data in the backup archive and is always used a whole. In practice, this design leads to the following limitations:

  • Since the logical volume structure is backed up in its entirety, selecting just one LVM volume out of many for backup means the volume structure of unselected volumes is still backed up.
  • When creating automatic mapping (step 12) of LVM volumes during restoration, the whole structure is also restored, even when restoring data for a smaller amount of volumes.

This means that the target system for restoration must contain the same or greater number of physical disks as the source system in order to fit the entire structure.

For example, your server contains two volume groups, VG1 and VG2 on four physical disks. Your critical system data is covered completely by VG1 and two physical disks, so you only select only volumes in this group during backup. If you want to map and restore this volume group automatically, your target must also contain at least four physical disks, because restoration of VG1 will also restore the structure for VG2, even though data from this second group is not contained in the backup. Volumes in VG2 will be empty of data after restoration

Solution

The only way to partially restore logical volumes is to map them manually before running the restoration task as described in our documentation.

More information

You can find all the details on backup and recovery of logical volumes in Linux in our product documentation, see Web Help: Backup and recovery of logical volumes and MD devices (Linux).

 

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