Hello, I wanted to present a backup system that I might be interesting. It uses one backup drive, not several.
Hour -- Type
01 Full
02 Inc-A
03 Inc-A
04 Inc-A
05 Inc-A
06 Inc-A
07 Inc-A
08 Inc-A
09 Inc-A
10 Inc-A
11 Inc-A
12 Inc-B ###
13 Inc-A
...
23 Inc-A
24 Inc-B ###
25 Inc-A
...
35 Inc-A
36 Inc-B ###
37 Inc-A
...
47 Inc-A
48 Inc-B and Diff-B ###
49 Inc-A
...
59 Inc-A
60 Inc-B ###
Inc-B will contain the difference to the last Inc-B (or Full). On hour 48, both a Diff and and Inc-B are created.
Advantages:
Differential images get larger and larger as time passes, forcing the user to create a new Full Image
Frequent incremental Images with no Differential images inbetween are high risk if an incremental depends on hundreds of previous incrementals
By creating "Inc-B" incrementals, we create a "mix" of the advantages of Differential and Incremtal backup:
Inc-B incrementals do not require any Inc-A incrementals, and not Differential images. Differential images are created less frequently, for additional safety.
As soon as the user uses Inc-B images, all Differential Backups will ALWAYS create an additional Inc-B backup AT THE SAME TIME. The user can therefore later choose to delete EITHER the Inc-B OR the Differential, because subsequent images will work irrespectively (because Inc-B and Diff are the exact same state). To indicate that this system is in use, Differentials are called "Diff-B".
The system also makes backups faster because fewer Differential Backups will be made and/or because the creation of an incremental at hour 1000 will not have to check 1000 previous incrementals, but only a fraction (the Inc-Bs).
For example Backup on day 43 requires:
Days 1, 12, 24, 36, 37, 38, 39, 40, 41, 42, 43
Instead of 1,2,3, .... 42, 43
Of course a similar system could also be created by automatically merging 6 old Incrementals into 1 and verifying the contents.
Hour -- Type
01 Full
02 Inc-A
03 Inc-A
04 Inc-A
05 Inc-A
06 Inc-A
07 Inc-A
08 Inc-A
09 Inc-A
10 Inc-A
11 Inc-A
12 Inc-B ###
13 Inc-A
...
23 Inc-A
24 Inc-B ###
25 Inc-A
...
35 Inc-A
36 Inc-B ###
37 Inc-A
...
47 Inc-A
48 Inc-B and Diff-B ###
49 Inc-A
...
59 Inc-A
60 Inc-B ###
Inc-B will contain the difference to the last Inc-B (or Full). On hour 48, both a Diff and and Inc-B are created.
Advantages:
Differential images get larger and larger as time passes, forcing the user to create a new Full Image
Frequent incremental Images with no Differential images inbetween are high risk if an incremental depends on hundreds of previous incrementals
By creating "Inc-B" incrementals, we create a "mix" of the advantages of Differential and Incremtal backup:
Inc-B incrementals do not require any Inc-A incrementals, and not Differential images. Differential images are created less frequently, for additional safety.
As soon as the user uses Inc-B images, all Differential Backups will ALWAYS create an additional Inc-B backup AT THE SAME TIME. The user can therefore later choose to delete EITHER the Inc-B OR the Differential, because subsequent images will work irrespectively (because Inc-B and Diff are the exact same state). To indicate that this system is in use, Differentials are called "Diff-B".
The system also makes backups faster because fewer Differential Backups will be made and/or because the creation of an incremental at hour 1000 will not have to check 1000 previous incrementals, but only a fraction (the Inc-Bs).
For example Backup on day 43 requires:
Days 1, 12, 24, 36, 37, 38, 39, 40, 41, 42, 43
Instead of 1,2,3, .... 42, 43
Of course a similar system could also be created by automatically merging 6 old Incrementals into 1 and verifying the contents.