RAID array creator

raid.sh

#!/usr/bin/env bash
set -euo pipefail

# Require: RAID name, mount path, RAID level
if [[ $# -ne 3 ]]; then
    echo "Usage: $0 <raid_name> <mount_path> <raid_level>"
    echo "Example: $0 data /mnt/data 0"
    exit 1
fi

raid_name="$1"
mount_path="$2"
raid_level="$3"
md_path="/dev/md/$raid_name"

# Require absolute mount path
if [[ "$mount_path" != /* ]]; then
    echo "Error: mount path must be absolute. Got '$mount_path'."
    exit 1
fi

# Check for existing RAID config
if grep -q "$md_path" /etc/mdadm/mdadm.conf 2>/dev/null; then
    echo "Error: RAID device '$md_path' already exists in mdadm.conf."
    exit 1
fi

# Check if mount path is already mounted
if mountpoint -q "$mount_path"; then
    echo "Error: '$mount_path' is already mounted."
    exit 1
fi

# Check if already in fstab
if grep -q -E "[[:space:]]$mount_path[[:space:]]" /etc/fstab; then
    echo "Error: mount path '$mount_path' already exists in /etc/fstab."
    exit 1
fi

# Discover eligible NVMe disks
disks=()
sizes=()
while IFS= read -r disk; do
    if lsblk -npr --output FSTYPE "$disk" | grep -q "linux_raid_member"; then
        continue
    fi
    size=$(lsblk -nbdo SIZE "$disk")
    disks+=("$disk")
    sizes+=("$size")
done < <(lsblk -dnp --output NAME | grep "^/dev/nvme")

if [[ ${#disks[@]} -eq 0 ]]; then
    echo "No eligible NVMe disks found."
    exit 1
fi

# Verify all disks are same size
first_size="${sizes[0]}"
for sz in "${sizes[@]}"; do
    if [[ "$sz" != "$first_size" ]]; then
        echo "Error: Disks are not the same size:"
        paste <(printf "%s\n" "${disks[@]}") <(printf "%s\n" "${sizes[@]}")
        exit 1
    fi
done

# Display disks
echo "The following disks will be used for RAID$raid_level:"
for disk in "${disks[@]}"; do
    echo "→ $disk"
    lsblk -d "$disk"
done

# Confirm
read -rp "Proceed with creating RAID$raid_level on these disks? This will erase all data. [y/N]: " confirm
if [[ "$confirm" != "y" && "$confirm" != "Y" ]]; then
    echo "Aborted by user."
    exit 1
fi

# Create the RAID array
mdadm --create --verbose "$md_path" \
    --level="$raid_level" \
    --raid-devices=${#disks[@]} \
    "${disks[@]}"

# Persist config and update initramfs
mdadm --detail --scan "$md_path" | tee -a /etc/mdadm/mdadm.conf
update-initramfs -u

# Format and mount
mkfs.ext4 "$md_path"
mkdir -p "$mount_path"
echo "$md_path $mount_path ext4 defaults,nofail,discard 0 0" | tee -a /etc/fstab
mount "$mount_path"

echo "RAID$raid_level array '$md_path' created and mounted at '$mount_path'."