Consider a site that performs a full backup every Sunday, a cumulative backup every Wednesday, and delta backups on the other days:
Day | Sunday | Monday | Tuesday | Wednesday | Thursday | Friday | Saturday |
Backup Type | F | D | D | C | D | D | D |
The full backup every Sunday contains all of the data for all of the tables. The delta backups on Monday and Tuesday contain only changed data blocks for those particular days. The Wednesday cumulative backup contains all changes from the Monday and Tuesday delta backups, plus any new changes. The Thursday, Friday, and Saturday delta backups contain only changes on each of those days.
If the site were to perform a restore of the delta backup image produced on a Friday, the following images would be restored:
- The full backup from the prior Sunday
- The cumulative backup from the prior Wednesday
- The delta backup from Thursday
- The delta backup from Friday