Configuring Btrfs in SUSE Linux Enterprise

Locate the empty disk (it will be the one with no partitions listed):

lsblk

Create the btrfs filesystem on the empty disk from Step 1:

sudo mkfs.btrfs /dev/nvme0n1

Create the btrfs directory:

sudo mkdir /btrfs

Mount the disk:

sudo mount /dev/nvme0n1 /btrfs

Change to the new /btrfs directory:

cd /btrfs

Create the "normal" directory:

sudo mkdir data

Copy the ssh directory to the data directory:

sudo cp -r /etc/ssh ./data

From the /btrfs directory, create the subvolume:

sudo btrfs subvolume create ./data1

Copy over the files from /data to /data1 (notice the . after data/):

sudo cp -r data/. ./data1

Remove the original directory:

sudo rm -rf data

Rename the subvolume:

sudo mv ./data1/ ./data

Verify the subvolume:

sudo btrfs subvolume list .

From the /btrfs directory, create a snapshot of data:

sudo btrfs subvolume snapshot ./data ./data-snap

Touch a file named file in data, and compare ./data to ./data-snap:

sudo touch data/file 
ls data
ls data-snap

Remove data/ssh/ssh_config, and compare to see it still exists in data-snap:

sudo rm data/ssh/ssh_config
ls data/ssh/ssh_config

The file should not be found.

Now verify it's in the snapshot:

ls data-snap/ssh/ssh_config

Delete data and then restore it from data-snap:

sudo btrfs subvolume delete data

sudo btrfs subvolume snapshot ./data-snap ./data

Verify with subvolume list:

sudo btrfs subvolume list .

Finally, verify the file you had deleted is back:

ls data/ssh/ssh_config