Background Information

My current (5 year old) laptop stores user-related data on two separate hard discs:-

1. 256 GB SSD - / and /home/ are separate btrfs subvolumes on this drive


2. 750 GB HDD - a special /home/data mount is created just for this hard disc

The separate /home/data structure allowed me to put almost all my data (documents, code, Dropbox/hubic/owncloud sync folders, music and video collection, archives of old projects) on the more spacious HDD, while keeping OS files on the SSD (along with ~/.config, ~/.emacs.d and all the other normal $HOME folders). Also, it proved useful more than a decade ago when I would dual-boot and needed /home/data to be on an NTFS partition which my windows install could access.

My backup strategy involves a manual backup script which runs rsync backups of /etc/, /home/, and /data/ to a 3TB hard disc attached permanently to my wifi router. A cron job on my wifi router does rsnapshots of those directories, while also using rsync to sync the latest copy over to another 3TB hard disc attached permanently to an off-site router (at my parent's house) also under my control. The off-site router is, in turn, an on-site backup to my parents, and is synced back to my router in the same fashion.

I've just gotten a new ultrabook and will be using it as my primary machine. As it only has one physical m2 SSD (512GB) I am considering using a more traditional file structure layout, with all user data under /home/myusername. Actually moving the data over to a new file structure is trivial, of course.

Problem Statement

What should I do with:-

1. The rsnapshot backups current duplicated on both wifi routers




2. The rsync folders on both wifi routers

Ideally, I would like to be able to achieve the following (in order of priority):-

1. I can just continue to run backups from my new machine using some variant of my old back up script (basically a bunch of rsync commands through sudo). This is crucial because any additional friction here reduces the likelihood of me actually doing backups...




2. I maintain all previously backed up information (my top level rsnapshots are monthly, so I have 12 months worth of backups (and weekly, and daily etc.)) without loss.




3. No duplication of backup data. My 3TB storage would not be able to accommodate a 100% duplicate of data from the process of moving from one laptop to another.




4. I can migrate to a different data/file structure based on a single /home/ partition. Lowest priority, I'll only do this migration if I have a clear path to success which fulfils all the above.

Possible solutions (not ideal)

One solution is simply maintaining the current directory structure with btrfs subvolumes. I can do this if needed, but I'd rather not.

Another solution would be to map my new structure to the existing subfolders in the current rsync structure. Also would rather avoid doing this (the first solution is actually more preferable) as this would mean the backup is quite different (in terms of where everything is) compared to the actual live system.

Thanks for reading, appreciate solutions to this conundrum. I was considering posting this on superuser, but I figured since all my machines and tools are Linux based the audience here is probably more appropriate.