https://drive.google.com/file/d/1mEMZ_sZg3Hy5VqWu5jW8U8ltQyfLruOV/view?usp=sharing

1. Understanding RAID-10 (1+0)

Key Concepts

• Hybrid RAID: Combines RAID-1 (mirroring) + RAID-0 (striping).
• Layout:
  • Lower layer: Mirrors (pairs of disks)
  • Upper layer: Stripes across mirrors
• Fault Tolerance:
  • Survives multiple disk failures—if no mirror pair is fully lost.
  • Example (4-disk): Can lose 1 disk per mirror pair (e.g., /dev/sda1 + /dev/sdc1).
• Capacity: 50% efficiency (e.g., 4×2TB → 4TB usable).
• Minimum Disks: 4 disks required (must be even number).
• Use Cases:
  • High-performance databases (MySQL, Oracle)
  • Virtualization hosts
  • Any workload needing max performance + redundancy

⚡ RAID-10 Advantage:

• Fastest rebuild time (only mirror partner needs sync)
• No parity calculations → better write performance than RAID-5/6

2. Creating RAID-10 Array

Prepare Disks

# Create partitions on 4 disks (e.g., /dev/sdb-sde)
for disk in sdb sdc sdd sde; do
  sudo fdisk /dev/$disk <<EOF
n
p
1

t
fd
w
EOF
done

sudo partprobe    # Reload partition table
lsblk             # Verify sdb1, sdc1, sdd1, sde1

Create RAID-10

# Create RAID-10 with 4 disks
sudo mdadm -C /dev/md0 -l 10 -n 4 /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1

# Verify
cat /proc/mdstat    # Shows [UUUU] (all disks active)
sudo mdadm -D /dev/md0    # Detailed status (note "Layout: n2" = near copies)

💡 Layout Note:

Default layout n2 = near copies (mirrors adjacent stripes). Most common and performant.

Format and Mount

sudo mkfs.ext4 /dev/md0
sudo mkdir /raid10
sudo mount /dev/md0 /raid10
df -hT              # Verify mounted

# Add test data
echo "cal" | sudo tee /raid10/cal
echo "date" | sudo tee /raid10/date