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Mattscreative edited this page Dec 5, 2025 · 2 revisions

Linux RAID Guide

Complete beginner-friendly guide to RAID configuration on Linux, covering Arch Linux, CachyOS, and other distributions including software RAID setup, RAID levels, and RAID management.

Table of Contents

  1. Understanding RAID
  2. RAID Setup
  3. RAID Management
  4. Troubleshooting

Understanding RAID

RAID Levels

Common RAID levels:

  • RAID 0: Striping (performance, no redundancy)
  • RAID 1: Mirroring (redundancy, 50% capacity)
  • RAID 5: Striping with parity (redundancy, 1 disk parity)
  • RAID 6: Double parity (redundancy, 2 disk parity)

Choose based on:

  • Performance: RAID 0
  • Redundancy: RAID 1, 5, 6
  • Capacity: RAID 0, 5, 6

RAID Setup

Install mdadm

Install RAID tools:

# Arch/CachyOS
sudo pacman -S mdadm

# Debian/Ubuntu
sudo apt install mdadm

# Fedora
sudo dnf install mdadm

Load Module

Load RAID module:

# Load module
sudo modprobe raid456

# Make permanent
echo "raid456" | sudo tee -a /etc/modules-load.d/raid.conf

Create RAID Array

Create RAID 1:

# Create RAID 1
sudo mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sda1 /dev/sdb1

# Check status
cat /proc/mdstat

Create RAID 5:

# Create RAID 5
sudo mdadm --create /dev/md0 --level=5 --raid-devices=3 /dev/sda1 /dev/sdb1 /dev/sdc1

Format and Mount

Format RAID:

# Format
sudo mkfs.ext4 /dev/md0

# Mount
sudo mount /dev/md0 /mnt/raid

RAID Management

Monitor RAID

Check status:

# Check status
cat /proc/mdstat

# Detailed info
sudo mdadm --detail /dev/md0

Add Disk

Add disk to RAID:

# Add disk
sudo mdadm --add /dev/md0 /dev/sdc1

# Grow array
sudo mdadm --grow /dev/md0 --raid-devices=3

Troubleshooting

RAID Failure

Replace failed disk:

# Remove failed disk
sudo mdadm --remove /dev/md0 /dev/sda1

# Add new disk
sudo mdadm --add /dev/md0 /dev/sdd1

Summary

This guide covered RAID for Arch Linux, CachyOS, and other distributions, including setup, management, and troubleshooting.

Next Steps

This guide covers Arch Linux, CachyOS, and other Linux distributions. For distribution-specific details, refer to your distribution's documentation.

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