About GFS

What Is GFS?

The Grandfather-Father-Son (GFS) policy features custom purge delays for some full backups to comply with archive storage requirements and optimize storage costs. The regular retention policy and GFS retention policy are combined to maintain backup data and keep the balance between data availability and storage expenses.

The GFS policy offers three different backup keeping periods:

• Yearly (grandfather)
• Monthly (father)
• Weekly backup (son)

According to the GFS policy settings, some full backups override regular retention policy settings. The purge delay for full backups selected according to the GFS retention policy can include the GFS delay and regular retention, depending on the GFS settings. Refer to the schemes below.

For the rest of the full backups, excluding the current generation, the purge delay will be applied according to the regular retention policy settings.

Scheme 1

Scheme 2

The GFS weekly, monthly, and yearly periods will be selected automatically based on the GFS settings. You can configure the custom purge delays for weekly, monthly, and yearly full backups marked as GFS restore points. Weekly backup is selected automatically and is retained on a weekly basis, monthly backup is selected automatically and is retained on a monthly basis, and yearly backup is retained annually.

How GFS Works

To apply the GFS policy, a full backup dataset is required. These backups must be completed without errors and warnings. If errors or warnings occur, the user is provided with solutions to resolve them.

At the end of backup plan execution, if the backup procedure is completed successfully and the GFS policy is enabled, the GFS search mechanism checks whether any GFS keeping periods can be assigned to the generation of this backup plan.

After the GFS keeping period is assigned, it remains unchanged until the end of this keeping period. This means that even if you change your GFS settings later, the keeping period will not change.

For example, if the following retention settings are set and the weekly GFS keeping period is enabled:

The search for weekly backup was started on Sunday, March 21, 2021, but for some reason, the first successful backup was completed on Friday:

This will be marked as the GFS weekly backup.

This backup will be kept until April 16, 2021, even if the GFS policy is disabled or changed later.

Subsequent incremental backups made by this backup plan will be kept according to the specified general retention policy:

GFS Keeping Period Assignment

The The The The GFS keeping period assignment engine runs at the end of any backup plan for backups that match all criteria (a successful backup with full backup dataset).

The GFS keeping period assignment engine searches for successful restore points according to the rules listed below:

• The yearly backup is searched for as of the first day of the month specified in the GFS settings. The first successful backup will be marked as yearly for this year. Some exclusions will apply:
  • If a year begins in the middle of the week and a weekly backup is already marked for the current week, the yearly backup is searched for as of the next Sunday.
• The monthly backup is searched for as of the first day of the month. Some exclusions will apply:
  • If a yearly backup is marked for this month, the monthly backup is searched for as of the next month.
  • If a weekly backup is already marked for the current week, the monthly backup is searched for as of the next Sunday.
• The weekly backup is searched for and assigned as of Sunday. Some exclusions will apply:
  • If a monthly or yearly backup is already marked in the current week, a weekly keeping period will be assigned in the next week.

Once a GFS keeping period is assigned, it is never changed.

Refer to the Examples chapter for more information.

Yearly (Grandfather)

The yearly restore point is selected once a year, starting from the month specified in the GFS settings (from January to December).

The first successful restore point that complies with the GFS policy and with user settings (you can select the month the yearly keeping period will be selected as of) is selected as yearly.

The yearly restore point selection can be postponed to the first Sunday if the weekly restore point is already selected for the first week of the year.

A yearly restore point is kept on backup storage for a specified number of years. The GFS retention period for this restore point remains the same even if the GFS policy is disabled or changed.

Monthly (Father)

A monthly restore point is marked once a month.

The first successful restore point that complies with the GFS policy will be marked as monthly.

The monthly restore point selection can be postponed to the first Sunday if the weekly restore point is already selected for the first week of the month. If there are no restore points that comply with the GFS policy criteria in January, then no monthly restore points for January will be assigned.

A monthly restore point is kept in the backup storage for a specified number of months. The GFS retention period for this restore point remains the same even if the GFS policy is disabled or changed.

Weekly (Son)

A weekly restore point is marked once a week as of Sunday.

A restore point with a weekly keeping period is kept in backup storage for a specified number of weeks. The GFS retention period for this restore point remains the same even if the GFS policy is disabled or changed. If there are no successful restore points that comply with the GFS policy criteria within a week, no weekly restore points will be marked with a weekly keeping period.