Differential backup merge

[maxhgm]

Why do differential backups merge when an older one is discarded due to the 'keep n last' rule? This merging makes sense for incremental backups, but why does it apply to differentials too?

[admin]

Why do differential backups merge when an older one is discarded due to the 'keep n last' rule? This merging makes sense for incremental backups, but why does it apply to differentials too?

I'm sorry, in order to be able to check the integrity of the image sequence when checking the backup image files, all backup versions store information for all previous backup versions. For example, the user makes a backup sequence as follows:
V1 Full
V2 Differential
V3 Differential
V4 Differential
V5 Differential
V6 Differential
...

If the information of V1~V3 is not saved in V4, the program will not be able to detect the abnormal loss of V2 and V3. Although the loss of V2 and V3 does not affect the restoration of data from V4 and subsequent backup versions (V5, V6...), but the program needs to report the loss of V2 and V3 to the user when performing image checking. Therefore, when Hasleo Backup Suite merges V2 and V3 in the backup sequence, it will correct the information of the previous versions stored in the subsequent versions.