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Raspberry Pi RAID NAS Server Setup

  • Raspberry Pi 4 (4GB RAM)
  • Micro SD card 64GB
  • 2x Integral USB 3.1 flash drives 128GB

OS: - Raspbian Bullseye


  1. Insert drive and list existing partition tables:
$ sudo fdisk -l
  1. Unmount drive (if needed):
$ sudo unmount /media/pi/<HARD-DRIVE-LABEL>
  1. Partitioning:

$ sudo fdisk /dev/sda
[m] for help

  1. Formatting:

$ sudo mkfs.ext4 /dev/sda1


  1. Repeat steps 1-4 above for other drives.


  1. Update system and install 'mdadm' RAID package:
$ sudo apt-get update
$ sudo apt-get upgrade
$ sudo apt-get install mdadm
  1. Find out the mount points for each drive:

$ blkid
$ lsblk

  1. Create RAID volume/array:

Linear Mode

$ sudo mdadm --create --verbose /dev/md0 --level=linear --raid-devices=2 /dev/sda1 /dev/sdb1

RAID-0 (Stripe Mode)

$ sudo mdadm --create --verbose /dev/md0 --level=stripe --raid-devices=2 /dev/sda1 /dev/sdb1
$ sudo mdadm -Cv /dev/md0 -l0 -n2 /dev/sd[ab]1

RAID-1 (Mirror Mode)

$ sudo mdadm --create --verbose /dev/md0 --level=mirror --raid-devices=2 /dev/sda1 /dev/sdb1
$ sudo mdadm -Cv /dev/md0 -l1 -n2 /dev/sd[ab]1


$ sudo mdadm --create --verbose /dev/md0 --level=4 --raid-devices=3 /dev/sda1 /dev/sdb1 /dev/sdc1
$ sudo mdadm --create --verbose /dev/md0 --level=5 --raid-devices=3 /dev/sdb1 /dev/sdc1 /dev/sdd1 --spare-devices=1 /dev/sde1
$ sudo mdadm --create --verbose /dev/md0 --level=6 --raid-devices=4 /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1


$ sudo mdadm --create --verbose /dev/md0 --level=10 --raid-devices=4 /dev/sda1 /dev/sdb1 /dev/sdc1 /dev/sdd1

  1. Confirm RAID array:
$ cat /proc/mdstat
  1. Save RAID array:
$ sudo -i  
$ mdadm --detail --scan >> /etc/mdadm/mdadm.conf  
$ less /etc/mdadm/mdadm.conf  
$ exit
  1. Create file system:
$ sudo mkfs.ext4 -v -m .1 -b 4096 -E stride=32,stripe-width=64 /dev/md0

NOTE: To change advanced parameters after creation if needed:

$ tune2fs -E stride=n,stripe-width=m /dev/md0

  1. Create mount point and mount file system:
$ sudo mkdir /mnt/raidx  
$ sudo mount /dev/md0 /mnt/raidx

NOTE: To change the owner of the mount point to pi:

$ sudo chown pi:pi /mnt/raidx

  1. Check content of the mounted file system:
$ ls -la /mnt/raidx
  1. Confirm its capacity:
$ df -h -x devtmpfs -x tmpfs
  1. Update the initial file system (Raspberry Pi uses a RAM disk image when booting up and we want to include our array):

    $ sudo update-initramfs -u
  2. Check UUID of mounted file system:

    $ blkid
    $ ls -l /dev/disk/by-uuid

  3. Add to fstab (make the drive permanent and auto mount drive at boot):

    $ sudo nano /etc/fstab

    Enter new line before the bottom comments and add:

    UUID=(my_uuid) /mnt/raidx ext4 defaults,noatime 0 0  

    Save and exit:

  4. Retrieve drive parameters and test speeds (optional):

    $ sudo hdparm -I /dev/md0
    $ sudo hdparm -tT --direct /dev/md0
  5. Reboot:

    $ sudo reboot
  6. Useful commands/Manage Mode:

    $ cat /proc/mdstat : show status of all RAID devices
    $ mdadm --detail /dev/md0 : detailed information about RAID md0 (mdadm -D)
    $ mdadm --detail --brief /dev/md0 : for shorthened/brief details (mdadm -Db)
    $ mdadm --query /dev/md0 : quick human-readable summary of RAID md0 (mdadm -Q)
    $ mdadm --examine /dev/sdx : information about RAID component device sdx (mdadm -E)
    $ mdadm --stop /dev/md0 : stop RAID device md0
    $ mdadm --assemble --scan : restart/assemble RAID device


  1. Install SAMBA:
$ sudo apt-get install samba samba-common-bin
  1. Set up SAMBA password (for user pi):
$ sudo smbpasswd -a pi
  1. Edit SAMBA config file:
$ sudo cp /etc/samba/smb.conf /etc/samba/smb.conf.bak  
$ sudo nano /etc/samba/smb.conf

Scroll all the way down to the bottom of the file and add the following code to create NAS file share:

# NAS Share Block  
path = /mnt/raidx  
comment = RPI4 RAID0 NAS Server  
volume = NAS-Server  
valid users = pi  
read only = NO  
guest ok = NO  
public = NO  
writable = YES  
browsable = YES  
### -rwxr--r--  
create mask = 0744  
### -rwxr-xr-x  
directory mask = 0755  
### All hosts on the 192.168.142 subnet allowed:  
hosts allow = 192.168.142.  

Save and exit:

  1. Check configuration file for internal correctness:
$ testparm
  1. Restart SAMBA service:

$ sudo /etc/init.d/samba restart
$ sudo service smbd restart

  1. Reboot ?
$ sudo reboot


  1. Open Finder

  2. Menu "Go" ⟶ "Connect to Server..."

Address: [smb://rpi4/NAS]

  1. [Connect]

  2. Connect As:

  3. Registered User

Name: pi
Password: ●●●●●●●●

  1. [Connect]


Commands to check¤

$ rsync options source destination : remote/local file-copying tool
$ rsync -ahv /mnt/u1/ /mnt/u2/ : example of the above

RAID Levels¤

Number of Drives /
RAID Level Availability:

2 /
RAID-0 Stripe (Fastest, but no redundancy)
RAID-1 Mirror (Excellent redundancy, good speed)

3 /
RAID-0 Stripe (Fastest, but no redundancy)
RAID-4 Dedicated parity disk (Good speed & redundancy)
RAID-5 Block-level striping with distributed parity (Excellent speed & redundancy)

4 /
RAID-6 Block-level striping with two parity blocks distributed across all member disks (Excellent speed & redundancy)
RAID 10 (nested RAID 1+0) (Excellent speed and redundancy)


mdadm(8) - Linux man page
How To Manage RAID Arrays with mdadm
Advantages and disadvantages of various RAID levels
RAID setup
A guide to mdadm
Characteristics of Linux RAID levels
Build your own Raspberry Pi NAS
How to Setup a Raspberry Pi Samba Server
Build a Raspberry Pi RAID NAS Server – Complete DIY Guide
Partitioning, Formatting, and Mounting a Hard Drive in Linux