Now my data volumes are separate from the system. I used raid for redundancy on the physical machine with another drive for differential filesystem level backups (snapshot every day for 60 days with only differential storage cost, see rdiff-backup). When I upgrade I just add new drives, assign them into the raid, wait for them to sync, and remove the old drives. By generational I mean my storage and how I do things aren't going to change when I reset things like they used to. All my data is outside the system I'm using and must be attached.

I can for example, spin up an AWS machine, run the package install commands for the apps I normally use, VPN to my fileserver and mount my home directory and project volumes, and in quite literally about 15-30 minutes have the exact same environment as I do at my house. CFEngine et al would speed that up quite a bit.