Le 08/11/2022 à 04:49, hw a écrit : [...]
When I want to have 2 (or more) generations of backups, do I actually want deduplication? It leaves me with only one actual copy of the data which seems to defeat the idea of having multiple generations of backups at least to some extent.
[...]I would think there is also a confusion here (in my opinion, but I may be wrong):
- deduplication is the action of preventing or correcting an object from having multiples occurences. The criteria here is: are objects identical?
- incremental/differential backup(2) is the action of backuping only objects (or deltas of objects) that have varied between backups. Thus forbiding duplicates (on the target storage) of objects that have not varied. But that definitely does not suppress duplicates on the source storage (that you want to backup) nor prevent to backup these duplicates, thus having duplicates on the target storage
(1) Wikipedia article on deduplication https://en.wikipedia.org/wiki/Data_deduplication(2) Wikipedia article on Backups, with incremental, differential, dedduplications explanations:
https://en.wikipedia.org/wiki/Backup#Deduplication