Restoring an image

There are some items to consider before you begin restoring images on your system.

Before you restore an image (offline or online), you must have administrative authority on the system.

Here is a list of items to consider before you restore an image:

• Restoring the image of a volume restores the data to the same state that it was in when you performed your last image backup. Be absolutely sure that you need to restore an image, because it replaces your entire current file system or raw volume with the image on the server.
• The image restore operation overwrites the volume label on the destination volume with the one that existed on the source volume.
• Ensure that the volume to which you are restoring the image is at least as large as the image that is being restored.
• On Linux® systems, some file systems such as ext2, ext3, ext4, btrfs, and xfs use a universally unique identifier (UUID) to identify themselves to the operating system. If you create an image backup of such a volume and you restore it to a different location, you might have two volumes with the same UUID. If you use UUID to define your file systems in /etc/fstab, be aware that the backup-archive client might be unable to correctly mount the restored file system because the UUIDs conflict. To avoid this situation, restore the image to its original location. If you must restore it to a different location, change the UUID of either the original or restored volume before you mount the restored file system. Refer to the Linux documentation for instructions on how to change a UUID. You might also need to manually edit the /etc/fstab file so the original volume, the restored volume, or both volumes can be mounted.
• The file system or volume you are restoring to must be the same type as the original.
• The file system or volume you are restoring to does not have to be the same type as the original. The volume does not even have to be formatted. The image restore process creates the appropriately formatted file system for you.
• Ensure that the target volume of the restore is not in use. The client locks the volume before starting the restore. The client unlocks the volume after the restore completes. If the volume is in use when the client attempts to lock the file system, the restore fails.
• You cannot restore an image to where the IBM® Storage Protect client program is installed.
• If you created an image of the system drive, you cannot restore the image to the same location because the client cannot have an exclusive lock of the system drive. Also, because of different system component configurations, the system image might not be consistent across components (such as Active Directory). Some of these components can be configured to use different volumes where parts are installed on the system drive and others to non-system volumes.
• If you have run progressive incremental backups and image backups of your file system, you can perform an incremental image restore of the file system. The process restores individual files after the complete image is restored. The individual files restored are those backed up after the original image. Optionally, if files were deleted after the original backup, the incremental restore can delete those files from the base image.

  Deletion of files is performed correctly if the backup copy group of the IBM Storage Protect server has enough versions for existing and deleted files. Incremental backups and restores can be performed only on mounted file systems, not on raw logical volumes.

• If for some reason a restored image is corrupted, you can use the fsck tool to attempt to repair the image.

  You can use the verifyimage option with the restore image command to specify that you want to enable detection of bad sectors on the destination target volume. If bad sectors are detected on the target volume, the client issues a warning message on the console and in the error log.

  If bad sectors are present on the target volume, you can use the imagetofile option with the restore image command to specify that you want to restore the source image to a file. Later, you can use a data copy utility of your choice to transfer the image from the file to a disk volume.

• If for some reason a restored image is corrupted, you should run chkdsk to check for and repair any bad sectors (unless the restored volume is RAW).

  You can use the verifyimage option with the restore image command to specify that you want to enable detection of bad sectors on the destination target volume. If bad sectors are detected on the target volume, the client issues a warning message on the console and in the error log.

  If bad sectors present on the target volume, you can use the imagetofile option with the restore image command to specify that you want to restore the source image to a file. Later, you can use a data copy utility of your choice to transfer the image from the file to a disk volume.