The database administrators at site B have determined the following availability requirements. The table below provides examples.

Table 1. Sample moderate availability requirements
Question Answer Recovery technique
How many committed transactions can you afford to lose? 1 day of transactions Perform daily backups.
How long can the application be offline while you perform scheduled maintenance? 8 hours per week Perform weekly offline backups with daily online full or incremental backups.
How long can you spend recovering if the database becomes unavailable? 8 hours Keep a full backup and one incremental or AI file.
Must distributed transactions occur consistently across databases? No Do not implement two-phase commit.

Given these requirements, the database administrators perform a full offline backup every Saturday night. Because they can lose only one day of transactions, they supplement weekly backups with daily online incremental backups. Because they can only allow time to restore a single incremental, they perform incremental backups with an overlap factor of six. This means that each incremental backup saves changes that were saved in the last six incremental backups. The full backup is tested Saturday night, and after the incremental backups finish, they are tested using disk space reserved for that purpose.