3.2.1. Arranging backup requirements¶

　There are various requirements related to backup. When considering the optimal backup method for your environment, it is necessary to decide what needs to be backed up and how backup needs to be done.

　In this section, we explain reference information for deciding target of backup and what type of backup is available.

(1) Organize target of backup. (Consideration of capacity that is required for backup)

Target	Usage application
Unit of disk/volume (Image backup)	Protect the entire server and system region. There are many files and folders to be protected. There are many servers to be protected.
Unit of file/folder (File backup)	Protect only specific file and folder.

* It is necessary to consider the retention period of the archive that was backed up.

(2) Organize type of backup. (Consider the length of time that is required for backup.)

Type	Description	Advantages	Disadvantages
Complete	All target data are imported and these data are used as basis of incremental backup and differential backup.	Recovery can be done independently so that the recovery time is short.	Backup time is long. Backup size is large.
Incremental	Only changes are imported. At the time of restoration, all incremental backup and the latest complete backup are used.	Backup time is short. Backup size is small.	If there are multiple incremental backup, data cannot be restored if one backup is damaged.
Differential	Only changes from the last complete update are imported. At the time of restoration, the latest incremental backup and the latest complete backup are used.	Backup time is short. (Backup time is longer than the incremental backup) Backup size is small. (Larger than the incremental backup)	If backup is frequently performed from the last complete backup, the backup size becomes large.

3.2. About configuration image

3.2.2. Usage patterns