Backup rotation/retention scheme is the how long the backup is retained on the media, many techniques have evolved over time to balance the data retention and the restoration costs.
Grandfather-father-son is a very common scheme used in the backup retention strategy. In which there are three or more backup cycles such as daily, weekly and monthly. the daily backups are rotated on daily basis using FIFO mechanism, the weekly backups are rotated on a weekly basis and the monthly on a monthly or quarterly basis.
Common example
The hourly backup (son) are rotated on hourly with one promoted to father status end of day
Daily backup or father backups are rotated on a weekly basis and promoted to Grandfather end of the week
Weekly backup or grandfather are rotated every month.
Sometimes the backups are removed from the site and archive to the secondary site for safekeeping
Different Backup Types Example
Some backup tools are providing the different backup types, in this case instead of making the son promoted to father and grandfather we use the different backup technique to create the backup
Say, Weekly (Grandfather) are full backup and archive to a secondary site and rotate monthly, daily (Father) full backup keep it only on primary and rotate it every week and the Hourly (son) are an incremental backup and keep it till the next full backup
How to achieve in public Cloud
In public cloud like AWS / Azure, / GCP you can create log backup of database server every hour and EBS / Volume snapshots, every day and every week do the snapshot copy to DR location / another region in the Cloud
Also published on Medium.
