Simple definition
Grandfather-Father-Son retention keeps multiple generations of backups, typically daily, weekly, and monthly.
Purpose and use
GFS, Grandfather-Father-Son, organizes backup generations to cover both recent and longer-term recovery requirements.
How does it work?
Daily points can be complemented by weekly, monthly or yearly generations. Backup software defines exactly which points receive these markers.
Example and verification
Verify that each expected generation has an available, recoverable point, especially after schedule or job changes.
Points to watch
A GFS generation is not automatically a physically independent copy or an off-site repository. Multiple markers can also apply to one point depending on the product.
In short
GFS structures historical coverage; copy separation and protection need complementary design.