When using AdvancedCopy Manager to back up data, a backup volume with the same capacity as a transaction volume is automatically selected from the available registered backup volumes.
If a specific backup volume is to be used to back up a given transaction volume, a "Device map file" must be created. A "Device map file" is a file defining the relationship between the transaction and a specific backup volume.
A device map file may be created anywhere on the Managed Server that performs backup. If you specify this file while performing a backup, the relationship as defined in the device map file is automatically recognized for that backup operation.
Point
To manage multiple generations of backups using defined transaction volume to backup volume relationships, multiple device map files must be prepared.
The device map file used when backing up or starting synchronous processing should meet either of the following requirements:
Either an unused backup volume must be specified
A backup volume detailed in the history information that was deleted by this backup must be specified.
Care should taken to ensure that the device map file is configured and used correctly where the backup system uses two or more backup volumes.
If the number of backup volumes prepared for synchronized high-speed backup is no more than the number of preservation generations, the backup can be performed by saving the backup volumes to secondary media, such as tape, and then deleting corresponding history information.
In such cases, the device map file specified at the start of synchronous backup processing is the file specifying the backup volumes that become available for reuse when history information is deleted.
The following provides an example of a device map file:
# A comment line starts with "#". # Business volume name Output destination backup volume name # Volume Group /dev/vg01 /dev/vg02 # A comment can be described here also. /dev/vg03 /dev/vg04 :
The rules for creating a device map file are as follows:
Describe a transaction volume name and a corresponding target backup volume name in one line. Separate the transaction volume name and backup volume name with one or more space or tab characters.
One or more space or tab characters may be used as delimiters between the beginning of a line and a transaction volume name or between the end of a target backup volume name and the end of a line (new line character).
A blank line (Space or tab characters) may be included in a file.
Anything after the symbol '#' is a comment. If the comment uses more than a single line, then each line must be preceded by a '#' character.
You cannot specify more than one backup volume for the same transaction volume in one device map file. If you do, only the first occurrence is valid. While the device map file is still read, subsequent occurrences are ignored.
A device map file may include descriptions of transaction volumes other than the processing target. Refer to the description example provided in the beginning of this chapter.
