BTRFS is a copy on write filesystem (COW)
Unlike journaling file systems like ext4, BTRFS does not overwrite the data when it is modified, instead it writes the data to a new block and changes metadata to point to the latest version of the file. This provides better protection against power failures.
Snapshots
BTRFS offers fast incremental snapshot creation and tools to backup and restore.
Creating the file system and btrfs partition
parted /dev/nvmexxx
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) mklabel gpt
(parted) mkpart primary btrfs 4MiB 100%
(parted) print
(parted) quit
after the partition is created, create the btrfs file system on it by running
sudo mkfs.btrfs /dev/sdxy
Mounting the partition
Temporary mount with
sudo mount /dev/sdxy /mountpoint
Show info about the btrfs
To see the UUID, size, usage of all btrfs disks.
sudo btrfs filesystem show
See detailed disk usage
sudo btrfs filesystem usage /Subvol
Creating the subvolumes
To create a subvolume called data
sudo btrfs subvolume create /mountpoint/data
List all the subvolumes
To create a subvolume called data
sudo btrfs subvolume list /mountpoint/data
Mounting the subvolumes
to make the mount permanent, edit the '/etc/fstab' file
UUID=DISKUUUD /MOUNTPOINT btrfs defaults,noatime,commit=120,compress=zstd:1 0 0
{: .nolineno file="/etc/fstab" }
These are mount options for the root subvol
- noatime : Do not modify metadata on file read. Reduces disk writes.
- commit=120: Time interval for writing changes to disk. Default is 30. Reduces disk writes.
- compress=zstd:1 : Filesystem level compression. Reduces disk writes.
Create a readonly snapshot of a subvolume
sudo btrfs subvolume snapshot -r /data /data/.snapshots/name
Copying snapshots to other drives using send, receive
Send and receive is faster than rsync. The destination must be also btrfs.
sudo btrfs send /data/.snapshots/name | sudo btrfs receive /mnt/backupDISK/backup
Restoring from a snapshot and make the snapshot writable
Copy the snapshot to the target folder.
sudo btrfs property set -tsf /data/snapshot ro false
Creating backups of your snapshot on a remote machine
btrfs send -p /data/ /data/.snapshots/new_snaphot | ssh root@ip "btrfs receive /mnt/backups"
