How Policies and Control Groups Work Together

The media, move, backup, and recovery policies are sometimes called function policies because they pertain to specific, core BRMS functional activities. The system policy is called a global policy because BRMS applies many of its values to the core functional activities.

Figure 3 illustrates the hierarchical relationship between policies and control groups.

Figure 3. The policy and control group hierarchy

As you can see, the system policy is global and encompasses the function policies and the control groups. Unless otherwise altered, the information contained in system policy parameters overrides information that is contained in function policy parameters. By the same token, function policy information, unless otherwise altered, overrides control group information.

However, because save and restore needs vary depending on customer needs, policies and control groups that share the same parameters and values can override one another. In this way, a function policy value can override a shared system policy value, and a control group value can override a shared function or system policy value. The following examples illustrate override capability:

• The system policy uses a default media policy that is called FULL, which indicates that, among other things, media must be kept for 35 days. Suppose, however, that you want to retain media for a longer period. In this case, you could specify the name of a different media policy in the backup policy at the Media policies for full backups field. In this way, a function policy can override a system policy value.
• A system policy default value instructs BRMS not to send a message to sign off interactive users before a save operation begins. There may, however, be occasions when the contents of a particular control group require that users be off the system during save processing. In that case, you would change the value in the Sign off interactive users field on the Change Backup Control Group Attributes display from *NO to *YES. *YES, in this instance, means that users cannot access that control group during save processing. In this way, a control group value can override a policy value.

BRMS comes with several predefined values (called defaults) so that you can immediately begin carrying out your backup, recovery, and media management operations. You can change all or any of the default values at any time to better reflect the needs of your company. If you have modified the default values, you can reset these back to the default values by running the INZBRM OPTION(*DATA) command.

BRMS also comes with predefined backup control groups that allow you to perform an immediate and comprehensive backup of your entire system. You can find more information about the default backup control groups in Backing Up Your Entire System. You can find additional information about BRMS policies in Tailoring Your BRMS Operations.