Tivoli Header

Tivoli Storage Manager for Windows Backup-Archive Clients Installation and User's Guide

Backup Image

The backup image command creates an image backup of one or more volumes on your system. These volumes can be formatted FAT, FAT32, NTFS, or unformatted RAW volumes. If a volume is NTFS-formatted, only those blocks used by the file system will be backed up. If you set the imagapsize option to 0, all blocks, including unused blocks at the end of the volume, will be backed up. See Imagegapsize for more information.

Note:
The API must be installed to use the backup image command.

Use the include.image option to include a file system or logical volume for image backup, or to specify volume-specific options for image backup.

Offline and Online Image Backup

The traditional offline image backup prevents access to the volume by other system applications during the operation.

If the LVSA is installed and configured, Tivoli Storage Manager performs an online image backup during which the volume is available to other system applications. See Performing an Image Backup (Windows 2000 Only) for information on how to install and configure the LVSA.

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.

During an online image backup, the following occurs:

  1. A snapshot of the logical volume is taken.
  2. Old data blocks containing changes made to the volume during the backup are saved into the OBF file (Old Blocks File).
  3. The OBF file is backed up to the server and the changes are applied to the volume image when you restore the volume.

You can use the following options to control an online image backup:

snapshotcachesize
Use this option with the backup image command, in the dsm.opt file, or with the include.image option to specify the maximum size of the OBF file. The value is a percent of the total size of the volume being backed up. The default value is 100 percent. See Snapshotcachesize for more information.

snapshotcachelocation
Use this option with the backup image command, in the dsm.opt file, or with the include.image option to specify the valid path to where the LVSA will create the OBF file. See Snapshotcachelocation for more information.

snapshotfsidlewait
Use this option with the backup image command or the include.image option when performing an online image backup to specify the amount of time that must pass in which there is no write activity on a volume before a snapshot is taken. See Snapshotfsidlewait for more information.

snapshotfsidleretries
Use this option with the backup image command or the include.image option when performing an online image backup to specify the number of additional times the LVSA should try to achieve the Snapshot FS Idle Wait time before the online image backup operation fails. See Snapshotfsidleretries for more information.

imagegapsize
Use this option with the backup image command, the include.image option, or in the dsm.opt file to specify the minimum size of empty regions on a volume that you want to skip during backup. See Imagegapsize for more information.

presnapshotcmd
Use this option with the backup image command, in the dsm.opt file, or with the include.image option to quiesce an application before the LVSA starts the snapshot. See Presnapshotcmd for more information.

postsnapshotcmd
Use this option with the backup image command, in the dsm.opt file, or with the include.image option to bring up an application after the LVSA starts a snapshot. See Postsnapshotcmd for more information.

Considerations

The following considerations apply to offline and online image backups:

Server-Free Image Backup (Windows 2000)

The Windows 2000 client supports SAN-based server-free data movement that off-loads data movement processing from the client and server processor and from the LAN during image backup and restore operations. Data is transferred directly between client disks and SAN-attached storage devices by a third-party copy function initiated by the Tivoli Storage Manager server. Tivoli Storage Manager will not compress or encrypt data during sever-free image backup.

If SAN errors occur, the client fails-over to a direct connection to the server or a connection to the storage agent and proceeds to move data via LAN-free or LAN-based data movement. When server-free data movement fails-over to LAN-free or LAN-based data movement, the data will not be compressed, even if you set the compression option to yes, to allow for a subsequent server-free restore of the image.

To enable SAN-based server-free support, the Tivoli Storage Manager Managed System for SAN feature must be installed and configured on the Tivoli Storage Manager Windows server. For an overview of the SAN-based server-free backup, see Appendix B, SAN-Based Server-Free Image Backup.

After the Tivoli Storage Manager Managed System for SAN feature is installed and configured on the Tivoli Storage Manager Windows server, use the enableserverfree option in your dsm.opt file. See Enableserverfree for more information.

When performing a server-free image backup, you must bind the volume to a management class that has a nonblocked destination storage pool; server-free paths must exist between all of the client disk(s), data mover, and storage pool. For more information, refer to Tivoli Storage Manager for Windows Administrator's Guide, GC32-0782.

The client can perform an offline or online image backup. If the LVSA is installed, the client performs an online volume image backup, allowing access to the volume by other system applications during the operation. See Offline and Online Image Backup for more information about options you should use to perform online image backups, and considerations that apply to online image backups.

Server-free backup is only available for NTFS-formatted volumes and raw volumes; FAT and FAT32 file systems are not supported. The following volume types are supported:

Special Considerations when Backing Up Images

When using the backup image command, it is important to be aware of special considerations if you want to do either of the following:

If You Intend to Perform a Point-in-Time Restore Later

To ensure that you can perform point-in-time restores of your file systems, including deleting original files which no longer exist on the logical volume, use a combination of full image backups and the incremental command as described in the steps below:

  1. Perform a full incremental backup of the logical volume, for example:
      dsmc incremental h:
    
  2. Perform an image backup of the same logical volume, for example:
      dsmc backup image h:
    
  3. Periodically, perform incremental backups, for example:
      dsmc incremental h:
    

You must follow these steps in the order shown to ensure that the server records additions and deletions accurately. The following command restores the file system to its exact state as of the last incremental backup:

  dsmc restore image h: -incre -del

If you do not follow the steps exactly, two things can occur:

Using the Mode Option

Two types of backup apply to logical volumes: mode=selective (the default) and mode=incremental. The mode=selective option creates and sends a full backup copy of the logical volume to the server. The mode=incremental option sends only those files that were added or changed since the last full image backup to the server. Tivoli Storage Manager ignores the -deletefiles option when the image+image incremental technique of backing up has been used.

If you use the backup image command, first with mode=selective followed by one or more executions with mode=incremental, use the incremental option with the restore image command to apply any changes made after the original image backup. The restore may include files that were later deleted plus the latest versions of files added or changed after the original image backup. If logical volumes are running at or near capacity, an out-of-space condition could result during the restore. For more information, see "Incremental-by-Date". The deletefiles option is allowed on the restore image command, but the client ignores it because the server is not aware of any deleted files.

The following restrictions apply:

Supported Clients

This command is valid for Windows 2000 only.

Syntax

                               .-----------------.
                               V                 |
>>-Backup Image--+----------+----+-------------+-+-------------><
                 '- options-'    +- filespec---+
                                 '- "filespec"-'
 
 

Parameters

options
You can use the mode and imagetype command line options with the backup image command. For more information, see Mode.

You can also use these common options: domain.image, exclude.image, include.image, imagegapsize, postsnapshotcmd, presnapshotcmd, snapshotcachelocation, snapshotfsidleretries, snapshotfsidlewait, snapshotcachesize. For information, see Chapter 9, Setting Processing Options.

filespec
Specifies the name of one or more logical volumes. Image backup is only supported on a volume that has a mount point assigned or a drive letter assigned. A volume without a drive letter or mount point cannot be backed up. If you want to back up more than one file system, separate their names with spaces. Do not use pattern matching characters. If you do not specify a file system, the logical volumes specified with the domain.image option will process. If you do not use the domain.image option to specify file systems to process, an error message displays and no image backup occurs.

Examples

Task
Back up a volume that has no drive letter but is mounted as a mount point.

Command: dsmc backup image m:\mnt\myntfs

Task
Back up the h: drive using an image incremental backup that backs up only new and changed files after the last full image backup.

Command: dsmc backup image h: -mode=incremental

Task
Perform an offline image backup of the f: drive during which the volume is unmounted and remounted read only.

Command: dsmc backup image f: -imagetype=static

Task
Back up the f: drive which is mapped to a volume which has not been formatted with a file system.

Command: dsmc backup image f:


[ Top of Page | Previous Page | Next Page | Table of Contents | Index ]