Backup Types

A backup schedule includes specification of the following three backup types:

Base	Backs up all the selected files.
Differential	Backs up all selected files that have changed since the last base backup of the same name. Before you can successfully run a Differential backup job, you must successfully complete a Base backup job with the same name.
Incremental	Backs up selected files that have changed since the previous backup (base, incremental, differential) with the same name. Before you can successfully run an Incremental backup job, you must successfully complete a Base backup job with the same name.

Each backup type may have different parameters such as a different timetable or a different output destination, but they must share the same input source. Therefore, a single backup definition includes all three backup types as well as all the parameters governing them.

Note. Multiple backup types are not scheduled for Block backup jobs because DPX intelligently determines the backup type for these modes.

The following table describes advantages and disadvantages for each backup type:

Backup Type	Advantages	Disadvantages
Base	• Minimizes media volumes required to restore during disaster recovery	• Takes the longest • Increases Catalog size the most • Uses the most media volumes
Incremental	• Takes the shortest time • Minimizes media volumes required • Minimal effect on Catalog	• Increases the number of media volumes required to restore during disaster recovery
Differential	• Compromise between base and incremental, providing some of the advantages of each	• Compromise between base and incremental, providing some of the disadvantages of each