btrfs: how to use and create snapshotable btrfs volume

gistfile1.txt

sudo apt-get install btrfs-tools

sudo su
mkdir /data
cd /data

# create 500 MB file
dd if=/dev/zero of=/data/datadisk  bs=1024  count=500000

# create btrfs
mkfs.btrfs -m single /data/datadisk

mkdir /mnt/datadisk
mount /data/datadisk /mnt/datadisk

# filesystem is mounted now

# create subvolume for data
btrfs subvolume create /mnt/datadisk/mydata

# store same data now to mydata

# create read-only snapshot
btrfs subvolume snapshot /mnt/datadisk/mydata /mnt/datadisk/snapshot-1 -r

# Additional commands:
# ====================

# list subvolumes (+snapshots)
btrfs subvolume list /mnt/datadisk

# delete snapshost:
btrfs subvolume delete /mnt/datadisk/snapshot-1