A Summary of Backup Models for Database Systems

This paper considers a backup models for database systems; A model of applied cumulative incremental backup and total backup and discrete model of incremental backup. The fundamental recovery technique for some medium failures in a database system is regularly carried out by executing a full backup that takes all copies of updated files. However, the overhead of such full backup becomes sometimes very large in a mass database system. To lessen the overhead of backups, an incremental backup with small overhead, which takes only copies of newly updated files, is usually adopted in most database systems. However, the overhead of an incremental backup increase in proportion to the total amount of updated files. It is shown that an optimal interval is given by a finite and unique solution of an equation under suitable conditions.