VSS equivalent would be btrfs snapshots or zfs snapshots.

Can you really copy a VSS to a new disk? For a new install, at some point you’ll need to reboot and go offline, so I don’t see the point in trying to keep uptime. If uptime matters, dont upgrade a disk, replace the entire system.

You can, and there are a number of options.

Easiest IMO is to install both drives, and then use dd to copy drive A to drive B, and then resize the partitions with gparted to fill the rest of the disk.

Do this from a live USB so that your not currently using drive A.

https://serverfault.com/a/4912

Note that /dev/sda might not be your first disk, so make sure you get them correct. Gparted can help you identify your disks.

WINED LOVER RIDES - probably not wrong, but interesting name for their variable :D

Are you using docker compose scripts? Backup should be easy, you have your compose scripts to configure the containers, then the scripts can easily be commited somewhere or backed up.

Data should be volume mounted into the container, and then the host disk can be backed up.

The only app that I’ve had to fight docker on is Seafile, and even that works quite well now.