From your local workstation, you can back up a logical volume as a single object (image backup) on your system.
The traditional static image backup prevents write access to the volume by other system applications during the operation.
You must be a root user to perform
this task, and image backup does not apply to Mac OS X.
These volumes can be formatted
NTFS or ReFS, or unformatted RAW volumes. If a volume is NTFS-formatted,
only those blocks that are used by the file system or smaller than
the imagegapsize parameter are backed up.
Normally you cannot restore an image backup
of the system drive over itself since an exclusive lock of the system
drive is not possible. However, in a Windows pre-installation
environment (WinPE), an image restore of the system drive is possible. For
information about restoring data in a WinPE environment, see Tivoli Storage Manager Recovery Techniques Using Windows Preinstallation Environment (Windows PE), which is
available on the web at http://www.ibm.com/support/docview.wss?uid=swg27005028.
You cannot restore an image backup to the volume
on which the client is running. Consider installing the Tivoli® Storage Manager client on the system
drive.
Image backup does not guarantee consistency
of system objects, such as the Active Directory. System objects can
be spread out across multiple volumes, and should be backed up by
using the backup systemstate command.
An image backup provides the following benefits:
- Backs up file systems that contain a large number of files faster than a full file system incremental backup.
- Improves the speed with which Tivoli Storage Manager restores file systems that contain many small files.
- Conserves resources on the server during backups since only one entry is required for the image.
- Provides a point-in-time picture of your logical volume, which might be useful if your enterprise must recall that information.
- Restores a corrupted file system or raw logical volume. Data is restored to the same state it was when the last logical volume backup was performed.
The traditional static image
backup prevents write access to the volume by other system applications
during the operation. Use the dynamicimage option
to back up the volume as is, without remounting it read-only. Corruption
of the backup can occur if applications continue to write to the volume
while the backup is running. Writing to a volume while an image backup
is running can result in inconsistent data and data loss after a restore
operation is run. The dynamicimage option overrides
the copy serialization value in the management class to perform an
image backup. After restoring an image backup taken with the dynamicimage option,
always run the chkdsk utility.
The traditional offline image backup prevents
write access to the volume by other system applications during the
operation. When you backup an image by using snapshotproviderimage=none,
always run the fsck utility after you restore the
data.
To restore an image backup of a volume, the Tivoli Storage Manager client must be able to obtain an exclusive lock on the volume that is being restored.
Restriction: Do not
use Tivoli Storage Manager
dynamic image backups for file systems, because the file system might
provide inconsistent data even when there is no write activity. Also,
dynamic image backup might result in a fuzzy image, which might not
be valid or complete when restored. If the Tivoli Storage Manager client fails to mount
the file system after it restores an image, run fsck.
However, running fsck can affect the integrity
of large amounts of data. Do not use dynamic image backup for AIX® JFS2 file systems. The Tivoli Storage Manager client
does not allow dynamic image backup for AIX JFS2
file systems. If you specify dynamicimage=yes for
a JFS2 file system, the Tivoli Storage
Manager client performs a snapshot-based image backup. If the snapshot
cannot be created for some reason, the Tivoli Storage Manager client instead performs
a static image backup.
Attention: To prevent
data loss, avoid using the dynamicimage option, and
ensure that there is no write activity on the volume while the backup
is in progress. For AIX JFS2
file systems, the amount of data that is backed up to the Tivoli Storage Manager server
during static or snapshot image backup is reduced by backing up only
those blocks used by the file system or smaller than the imagegapsize option.
This method of backing up your data improves the performance of image
backup. For more information, see Imagegapsize.
For AIX clients
only: By default, Tivoli Storage
Manager performs an online snapshot image backup of JFS2 file systems,
during which the volume is available to other system applications.
For Linux clients only: By
default, Tivoli Storage Manager performs
a snapshot image backup of file systems that exist on a logical volume
that is created by the Linux Logical
Volume Manager. The volume is available to other system applications
while the snapshot image backup is performed.
If the Tivoli Storage
Manager online image support is configured, Tivoli Storage Manager performs an online
image backup, during which the volume is available to other system
applications. The snapshot provider, as specified by the snapshotproviderimage option,
maintains a consistent image of a volume during online image backup.
You can use the snapshotproviderimage option
with the backup image command or the include.image option
to specify whether to perform an offline or online image backup.
Attention: File systems
that are managed by Tivoli Storage
Manager for Space Management are not enabled for image backup.