Understand the complete, differential and incremental backup of data in one minute

Commonly used data backup methods are full backup, differential backup and incremental backup, so what is the difference between these three backup methods, how to choose in specific applications?
1, Introduction to backup methods
Full backup (Full Backup)
backup all selected The folder does not depend on the archive attribute of the file to determine which files to back up. During the backup process, any existing marks are cleared, and each file is marked as backed up. In other words, clear the archive attribute.
A full backup refers to a complete copy of all data or applications at a certain point in time. In practice, a tape is used to fully back up the entire system, including the system and all data. The biggest advantage of this backup method is that as long as a tape is used, the lost data can be recovered. Therefore, the recovery time of the system or data is greatly accelerated.
Differential backup (Differential Backup)
backs up data that has changed since the last full backup. During the differential backup process, only the marked files and folders are backed up. It does not clear the mark, that is, it is not marked as a backed up file after backup. In other words, the archive attribute is not cleared.
Differential backup refers to the backup of those files that have been added or modified after a full backup to the time of differential backup. When restoring, we only need to restore the first full backup and the last differential backup. Differential backup has its own advantages while avoiding the shortcomings of the other two backup strategies.
First, it has the advantages of short backup time and saving disk space; second, it has the characteristics of less tape and shorter recovery time required for full backup recovery. The system administrator only needs two tapes, the full backup tape and the differential backup tape the day before the disaster, to restore the system.
Incremental backup (Incremental Backup)
backs up data that has changed since the last backup (including full backup, differential backup, and incremental backup). During the incremental backup, only the marked files and folders are backed up, it clears the mark, that is: mark the file after backup, in other words, clear the archive attribute.
Incremental backup means that after a full backup or the last incremental backup, each subsequent backup only needs to back up the files that have been added and modified compared to the previous one. This means that the object of the first incremental backup is the increase and modification of the file generated after the full backup; the object of the second incremental backup is the increase and the modification of the file after the first incremental backup. Files, and so on.
The most obvious advantage of this backup method is: there is no duplicate backup data, so the amount of backup data is not large, and the time required for backup is very short.

2. The difference between differential backup and incremental backup
Through the above conceptual analysis, we can know that the difference between differential backup and incremental backup is that they have different reference points for backup: the reference point of the former is the last full backup, differential backup or incremental backup The reference point of the latter is the last full backup.
The following figure shows the difference between differential backup and incremental backup, Cumulative is differential backup, Differetial incremental backup:

3. Examples of different backup types combined application
① Full backup and differential backup
take weekly data backup plan as an example, we can Perform a full backup on Monday and a differential backup from Tuesday to Friday. If the data is destroyed on Friday, you only need to restore Monday ’s full backup and Thursday ’s differential backup. This strategy requires more time to back up data, but less time to restore data.
② Full backup and incremental backup
Taking weekly data backup as an example, full backup is performed on Monday, and incremental backup is performed from Tuesday to Friday. If the data is destroyed on Friday, you need to restore normal backups on Monday and all incremental backups from Tuesday to Friday. This strategy takes less time to back up data, but restores data takes more time.
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