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From your local workstation, you can back up one or more volumes or raw logical volumes as a single object (image backup) on your system.
An image backup provides the following benefits:
The traditional offline image backup prevents access to the volume by other system applications during the operation. Use the imagetype=dynamic option to back up the volume as is without remounting it read-only. Corruption of the backup may occur if applications write to the volume while the backup is in progress. In this case, run chdsk after a restore. This option replaces the dependency on the Copy Serialization value in the management class to perform an image backup without unmounting and remounting the file system read-only. See Imagetype for more information.
For Linux86 only: By default, Tivoli Storage Manager performs an online image backup of file systems residing on a logical volume created by the Linux Logical Volume Manager during which the volume is available to other system applications.
You can use the imagetype option with the backup image command or the include.image option to specify whether to perform an offline or online image backup. See Imagetype for more information.
Before you perform an image backup, please consider the following:
If the client cannot lock a volume because it is in use, and online image backup is not available, you can use an include.image statement to force the client to continue the image backup without unmounting and remounting the volume in read-only mode. Set the imagetype option to dynamic in the include.image statement. The backup may be corrupted if applications write to the volume while the backup is in progress. This may be corrected by running chkdsk after a restore to fix any corrupted blocks. See Include Options for more information.
Important: If a mounted file system has nested mount points, unmount them before attempting a backup. Otherwise, Tivoli Storage Manager will be unable to unmount the volume.
We recommend that you do not include system files in an image backup because file systems being actively used cannot be unmounted.
The following table lists devices supported by the backup image
command. A raw device might be a disk slice, a partition, or a logical
volume.
Table 12. Volume Device Type Support for an Image Backup
Logical Volume Manager | Raw Device Types | Sample Device Name | Backup Image Command Support |
---|---|---|---|
AIX Logical Volume Mgr | Logical Volumes | /dev/lv00 | AIX, AIX 5L |
Sun Solstice Volume Mgr | Meta Devices | /dev/md/dsk/dl | Solaris |
Veritas Volume Mgr | Logical Volumes |
/dev/vx/dsk/rootdg/ vol01 | HP-UX, Solaris |
Raw Disk | Partitions | /dev/hda1, /dev/sda3 | Linux86 |
Linux Logical Volume Mgr | Logical Volumes |
/dev/myvolgroup/ myvolume | Linux86 |
Raw Disk | Disk Slices | /dev/dsk/c0tld0s0 | Solaris |
The client must support the raw device type on the specific platform in order to perform an image backup of a raw device. If you want to perform an image backup for a file system mounted on a raw device, the raw device must be supported. Remember to specify raw devices by their block device name.
You can perform an incremental-by date image backup to back up files that have changed since your last image backup. The following restrictions apply:
Use the backup image and restore image commands to perform offline or online image backup and restore operations on a single volume. See Backup Image and Restore Image for more information.
Use the mode option with the backup image command to perform an incremental-by-date image backup that backs up only new and changed files after the last full image backup. However, this only backs up files with a changed date, not files with changed permissions. See Mode for more information.
You must assign a mount point for the volume on which you want to perform an image backup. Tivoli Storage Manager will not back up a volume without a mount point.
To create an offline or online image backup of your file system or raw logical volume, perform the following steps:
The following is an example of how you can use image and incremental
backups together:
| Client | Server |
---|---|---|
Monday | Files 1, 2 and 3 reside here. | An image backup is performed. (Assume a full incremental was also performed.) |
Tuesday | File 4 is created. | Daily incremental is performed - including incremental for file 4. |
Wednesday | File 2 is deleted; file 3 is changed. | Daily incremental is performed - including incremental for file 3. |
Thursday | File 1 is deleted. | Daily incremental is performed. |
Suppose you want to use the image created on Monday to restore your file system as it appeared just after Thursday's incremental backup. You would enter the following command:
restore image filespace -incremental -deletefiles
Tivoli Storage Manager would then use the following process: