I use rsync to backup my filesystem on another hdd. However, I was looking for a solution to backup that directory onto another hdd, but in such a way that it can be stored into a compressed file (to save space on that second backup hdd), on the fly.
I thought about doing
rsync-> squashfs (just like this proposed solution), but it seems squashfs is more of a read-only filesystem, which has to be re-generated each time.I have experimented a little with fsarchiver, (as I'm typing this I found it does files/directories, not just full filesystems) but if I understand it correctly, full backup needs to be redone even for small changes.
I found this question where I learned about incremental backup with
7zip, which is "almost" what I want (just look at this), except that changes are not done "in place" (as rsync does), which means that my huge backup file would first require as much free space as the archive itself, which to me defeats the purpose. (A 700GB backup file on a 2TB drive could not be updated, for example). Or, I would have to opt for multiple 7z files to track the incremental changes, which I would rather not do, especially since I would face the same problem of having to delete the big file to get an updated single backup file.
So, is there a solution for me? A compressed file that I can either mount, or just run a command to perform the equivalent of an rsync command to only update the changed/added/deleted files in the archive? Or am I dreaming?
