Ubuntu – nother way for me to backup /home/user other than creating a subvolume


I think I'm having difficulty fully understanding subvolumes and snapshots.
The /home partition is btrfs. I want to create a "backup" snapshot of /home/user (for example) but user has existed for years (previously ext4 > btrfs-convert). I believe you can only make a snapshot of a subvolume. I checked and there are no "default" subvolumes already present.

1) Is there another way for me to backup /home/user other than creating a subvolume /home/user2 and copying everything from user to user2 in order to snapshot it?

Best Answer

It is perfectly reasonable to just snapshot the whole /home if you want /home/user to be backed up. snapshots are relatively cheep.

btrfs snapshot create /home/ /home/snapshot

In Btrfs the base unit of a snapshot is the subvolume (/mount-point/ is automatically a subvolume) and you cant snapshot anything smaller. In this case your /home is the smallest thing you can snapshot. You will likely never run into problems with snapshotting all of /home and if someday you do then you're method of creating a subvolume and copying into it will work to. there is a good chance that by then btrfs will be able to create snapshots of plain old directories anyway.