Understanding Backup Methods

 When planning a backup, the amount of time the backup job takes and the amount of storage used are key considerations. By backing up only the data that has changed, you can reduce both the time and storage space—but you must still be able to restore any data required, using those backups. This can be achieved by using full, differential and incremental backup ‘methods’.

These 3 backup ‘methods’ are described below

• A Full backup means that all of the data you selected is backed up each time the backup job runs. To perform a restore, all you need is the Full backup.
• A Differential backup means only data that has changed since the last Full backup, is backed up. To perform a restore, you need the last Full backup and the Differential backup from the day you want to restore from.
• An Incremental backup means only data that has changed since the last backup (e.g. last incremental backup) is backed up. To perform a restore you need the last Full backup and all Incremental backups up to the day you want to restore from.

A combination of Full plus Differential or Incremental backups can be implemented manually or automatically, depending on the backup type. This is because File Protection, File Archiving and System Protection use different backup technologies.

Traditionally, backups needed the method to be manually configured, as in the case of File Archiving. File Protection and System Protection manage the method automatically because they use advanced technologies that store and monitor data in different ways.

These 3 backup types are explained below

• File Archiving needs to have the backup method set manually. To do this, select the Backup tab’s Manage menu and then the backup job. Select Edit from the top menu and then Schedule from the left menu to display the scheduling options. The Customize schedule option will open a window where you can manually set the backup method for each day in your backup schedule.
• System Protection automatically manages the backup method because it uses imaging technology. This technology creates a full backup when a new destination is selected. Each time the backup job runs, the same image is incrementally updated with data that has changed. Copies of the data that are written over are maintained by virtual snapshots that enable multiple restore points.

• File Protection automatically manages the backup method because it uses single-instance store. This technology has the advantages of both incremental and full backups. After the initial full backup, each subsequent backup will contain only data that has changed. Data that has not changed will be represented by links to earlier backups (on the same destination) that contain that data.  This means each incremental backup will appear as a full backup and it will be the only backup you need to perform a restore.