Simplified Linux partitioning script for Seagate Mach.2 drives

partition_mach2.sh

#!/bin/bash

# Check if a LUN is provided as an argument
if [ -z "$1" ]; then
    echo "Usage: $0 <lun-from-/dev/disk/by-id>"
    exit 1
fi

# Validate the LUN path and ensure it's under /dev/disk/by-id
LUN="$1"
if [[ ! "$LUN" =~ ^/dev/disk/by-id/ ]]; then
    echo "Error: $LUN is not a valid path under /dev/disk/by-id."
    exit 1
fi

# Ensure the device exists
if [[ ! -b "$LUN" ]]; then
    echo "Error: $LUN is not a valid block device."
    exit 1
fi

# Variables
ZPOOL_NAME="MACH2"  # Default value for ZPOOL_NAME
ALIGN=$((1024*4))
GPT_OVERHEAD=34

# Default LOG_FILE to /dev/null if not set
LOG_FILE=${LOG_FILE:-/dev/null}

#=======================================================
# Run a command but first tell the user what it's going to do.
run() {
    # Print the command line, but trim extra white space.
    printf "$@ \n" | sed 's/\t/ /g' | sed 's/ \+/ /g' | tee -a "${LOG_FILE}"
    [[ 1 == $DRY_RUN ]] && return 0
    eval "$@"; ret=$?
    [[ $ret == 0 ]] && return 0
    printf " $@ - ERROR_CODE: $ret\n"
    exit $ret
}
#=======================================================

# Extract the serial number from the LUN name using awk
SERIAL=$(basename "${LUN}" | awk -F '_' '{print $NF}')

# Get the largest beginning and ending sectors using sgdisk
LARGEST_END="$(sgdisk -a ${ALIGN} -E ${LUN} | grep -v Creating)"
LARGEST_BEG="$(sgdisk -a ${ALIGN} -F ${LUN} | grep -v Creating)"

# Calculate the total sectors and the midpoint
TOTAL_SECTORS=$((GPT_OVERHEAD + LARGEST_END))
MID_LBA=$((TOTAL_SECTORS / 2))

# Run the sgdisk commands to create the two partitions
run "sgdisk -a ${ALIGN} -I \
--new=1:$LARGEST_BEG:$((MID_LBA-$ALIGN-1))   --change-name=1:${ZPOOL_NAME}_A_${SERIAL} \
--new=2:$((MID_LBA+$ALIGN)):0                --change-name=2:${ZPOOL_NAME}_B_${SERIAL} \
${LUN} >/dev/null"

# Wait for the commands to complete
sleep 1

# Run partprobe to update the partition table
run "partprobe"