Working with retention rules
A retention rule is an optional feature that allows you to implement granularity for backed up generations. For example, you might want to retain all generations from the previous day, one generation each day for a week, one generation each week for a month, one generation each month for a year, and one generation each year for 7 years. When using retention rules, you must know the nature of the backup data such as the number of generations and frequency of changes.
If you do not use a retention rule, your backup data remains online based on the maximum generation settings. This means the oldest generation of a file will be overwritten only when the configured maximum number of generations is reached. Generations are created in the DS-System online storage when the backup detects that a file has changed. Files that never change have only one generation.
After assigning a retention rule to a backup, you can enforce the retention rule on-demand or based on a schedule. When a retention rule is enforced, any data that does not qualify for retention is deleted.
When configuring a retention rule, consider the following:
• Ensure the retention rule works with the maximum number of generations for the backup. If the maximum number of generations is set to a low number (e.g. 7), the retention rule might not produce the intended result. because the oldest generations are likely to b overwritten by the backup process before any of the generations quality for deletion by the retention rule.
• Retention rules work best if the maximum generations parameter is configured to the maximum setting (9999) or a high number (e.g. 300). The retention rules help by deleting what you define to unnecessary and retaining online what you define to be critical.
• Due to the number of possible retention rule configurations, you should treat retention as if you are performing a manual deletion of data.
By default, enforcing a retention rule deletes all obsolete data from the DS-System online storage. However, a copy of the data can be sent to the BLM Archiver before it is removed completely from the DS-System online storage so you can effectively save a copy of every backup generation forever..
IMPORTANT: The system does not automatically delete backup data. This process must be performed by an authorized user. Apply caution when performing this process because data cannot be recovered after it has been deleted.