I would like to build a simple NAS using my Raspberry Pi 5, equipped with the Geekworm X1011 and an M.2 NVMe drives. This project will also provide me with the opportunity to use BTRFS for the first time.

Getting started

  1. To install BTRFS excecute the following commnad:

    sudo apt install btrfs-progs

  2. Uses lsblk to get the current partitions status

    $ lsblk 
NAME        MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS
mmcblk0     179:0    0  14.9G  0 disk 
├─mmcblk0p1 179:1    0   512M  0 part /boot/firmware
└─mmcblk0p2 179:2    0  14.4G  0 part /
nvme0n1     259:0    0 476.9G  0 disk 
└─nvme0n1p1 259:1    0 476.9G  0 part 
nvme1n1     259:2    0 238.5G  0 disk 
nvme2n1     259:7    0 238.5G  0 disk

  3. If needed remove the old partitions using fdisk, cfdisk or parted

BTFS Pool

I’m going to create a poll of discs, because at the time of writing I have 3x M.2 of different sizes, I decided not to use any RAID as I’ll be wasting some space that I don’t want. So I take the risk of losing data. The best way to use RAID is to have all the discs of the same size, otherwise the usable space for each disc is limited to the size of the smallest disc in the array.

  1. Create the mount point of the pool

    sudo mkdir /mnt/my_pool
sudo chown -R $USER:$USER /mnt/my_pool

  2. Create the BTRFS pool, in my case with the three disks

    sudo mkfs.btrfs -d single -L my_pool /dev/nvme0n1 /dev/nvme1n1 /dev/nvme2n1 -f

  3. Get your nearly created pool details

    sudo btrfs filesystem show

To get details about the BTRS pool

sudo btrfs filesystem usage /mnt/my_pool

Mount the pool

Now is time to mount your pool in /etc/fstab, get the UUID from the previus command and add following line

# My Pool mount options
MOUNT_OPTIONS="autodefrag,compress=zstd:3,discard=async,noatime,nodiratime,nodev,rw,space_cache=v2,ssd,user"

# Update fstab with new mount point
echo "UUID=<YOUR-UUID> /mnt/my_pool btrfs $MOUNT_OPTIONS 0 0" | sudo tee -a /etc/fstab

Some details about mount options:

  • autodefrag: enable automatic file defragmentation for small random writes in files with a maximum file size of 64K
  • compress=zstd:3: enables lossless Zstandard compression at level 3, focusing on a balance between speed and compression ratio.
  • discard=async: enables asynchronous TRIM operations, improving SSD performance by deferring TRIM commands to run in the background
  • noatime: allows measurable performance gains by eliminating the need for the system to write to the file system for files that are simply read
  • nodiratime: prevents updating directory access times, improving performance by reducing unnecessary write operations
  • nodev: disallows creating and accessing device nodes (used in particular for special files in /dev);
  • noexec: does not allow the execution of executable binaries in the mounted file system
  • nosuid: specifies that the filesystem cannot contain set userid files
  • rw: allows reading and writing
  • space_cache=v2: control the free space cache. This greatly improves performance when reading block group free space into memory
  • ssd: by default, Btrfs will enable or disable SSD allocation heuristics depending on whether a rotational or non-rotational device is in use
  • user: allows ordinary users to mount and unmount the filesystem