Raw Backup and Restore of Physical Disks and Volumes › How Raw Backup Works › Limitations on Performing Raw Backup and Restore Operations

Limitations on Performing Raw Backup and Restore Operations

Consider the following limitations when performing a raw backup of physical disks and volumes:

• Arcserve Backup does not support performing raw incremental and differential backups. If you submit such a backup job, Arcserve Backup will automatically change it to a full backup job.
• Arcserve Backup does not execute backups using Volume Shadow Copy Service (VSS) snapshot technology.
• Arcserve Backup does not support the backup and restore of physical disks or physical volumes for clusters. Therefore, these devices will not be displayed under the cluster virtual node in the Source tab of the Backup Manager.
• Arcserve Backup does not support the backup and restore of physical disks or physical volumes for removable media. Therefore, these devices will not be displayed in the Source tab of the Backup Manager.
• Backup jobs may fail when Arcserve Backup cannot obtain exclusive access to the device.
• When a dynamic physical disk is restored to another physical disk, Arcserve Backup does not copy the partition information to the destination physical disk. Therefore, the volumes and partitions of the source physical disk are not shown on the destination physical disk after the restore. In other words, you can restore dynamic disks only to their original location. In addition, if you have multiple dynamic disks, then you must restore all of these dynamic disks to their original locations to reinstate the original volume partitioning.

  The reason for restoring dynamic disks to their original location is:

  The partition table on a dynamic disk does not contain an entry for each volume on the disk because the volume information is stored in the dynamic disk database. Each dynamic disk of a system contains a replica of this dynamic disk database. The location of the database is determined by the partition style of the disk.

  • On Master Boot Record (MBR) disks, the database is contained in the last 1 megabyte (MB) of the disk.
  • On Globally Unique Identifier Partition Table (GPT) disks, the database is contained in a 1 MB reserved (hidden) partition known as the Logical Disk Manager (LDM) Metadata partition.

  As a result, unless this database is written to the disk during the restore, the partition information cannot be restored. For a system with multiple dynamic disks, all the disks have to be restored to their original locations because each disk contains a copy of the database, and database copies must be identical to restore the original partition information.

• The physical volumes corresponding to system or boot volumes and the disks on which these physical volumes reside are not displayed in the Source tab of the Backup Manager.
• The Filter option is not available for raw backup and restore of physical disks and volumes.