A management class is a collection of backup and archive copy groups that establishes and contains specific storage management requirements for backing up and archiving data.
An administrator can establish separate management classes to meet the backup and archive requirements for different kinds of data, such as:
- System data that is critical for the business.
- Application data that changes frequently.
- Report data that Management reviews monthly.
- Legal information that must be retained indefinitely, requiring a large amount of disk space.
Note: If you have the Tivoli® HSM client installed,
it can also contain specific requirements for migrating files to storage. 
Most of the work
you do with storage management policies is with management classes.
Each file and directory that you back up, and each file that you archive,
is associated with (or bound to) a management class, as follows:
- If your data is not associated with a management class, Tivoli Storage Manager uses the default management class in the active policy set.
- When backing up directories, you can specify a management class with an include statement or the dirmc option. If you do not specify a management class, Tivoli Storage Manager uses the management class in the active policy set specifying the longest "Retain Only" retention period. If there are multiple management classes that meet this criteria, Tivoli Storage Manager uses the last one found, in alphabetical order.
- For archiving directories, you can specify a management class with an include.archive statement or the archmc option. If you do not specify a management class, the server assigns the default management class to the archived directory. If the default management class has no archive copy group, the server assigns the management class that currently has the archive copy group with the shortest retention time.
You can use include statements in your include-exclude list to associate files with management classes. In your client options file, you can associate directories with a management class, using the dirmc option.
Within a management class, the specific backup and archive requirements are in copy groups. Copy groups define the specific storage management attributes that describe how the server manages backed up or archived data. Copy groups include both backup copy groups and archive copy groups. A management class can have one backup copy group, one archive copy group, both, or neither.
A backup copy group contains attributes that are used during the backup process to determine:
- How many days must elapse before a file is backed up again.
- How a file is processed during a backup if it is in use.
It also contains attributes to manage the backup versions of your files on the server. These attributes control:
- On which media type the server stores backup versions of your files and directories.
- How many backup versions the server keeps of your files and directories.
- How long the server keeps backup versions of your files and directories.
- How long the server keeps inactive backup versions.
- How long the last remaining inactive version of a file is kept.
An archive copy group contains attributes that control:
- Whether a file is archived if it is in use
- On which media type the server stores archived copies of your files
- How long the server keeps archived copies of your files