blink disk drive's led (useful for disk array using LSI Logic HBA to locate failed drive, etc.)

blink_disk_led

#!/bin/sh

# blink disk drive's led (useful for disk array using LSI Logic HBA to locate failed drive, etc.)
# https://gist.github.com/benok/c117badbfb6af744578d48e2ab1d4d4f
# (based from https://stackoverflow.com/a/4018229/26736)

# need blockdev(8) to clear disk cache on access

usage() {
    echo "${0##*/} [-n] device(sda,sdb,etc.)"
    echo "-n: suppress message"
}

opt_n=0

vecho() {
    if [ $opt_n != 1 ]; then
        echo $*
    fi
}

if [ ${1:-0} == '-n' ]; then
    opt_n=1
    shift
fi

if [ $# != 1 ]; then
    usage
    exit 1
fi

blockdev=$(which blockdev)
if [ $? != 0 ]; then
    echo 'need blockdev(8) to run properly'
    exit 1
fi

uid=`id -u`

if [ $uid != 0 ]; then
    echo 'you must be root.'
    exit 1
fi

diskDev=$1

while true; do
    vecho "accessing /dev/$diskDev..."
    blockdev --flushbufs /dev/$diskDev
    dd_err=$(dd if=/dev/$diskDev of=/dev/null bs=512 count=409600 conv=noerror 2>&1)
    if [ $? != 0 ]; then
        echo got error status $? from dd
        echo $dd_err > /dev/stderr
        exit 2
    fi	
	vecho "sleeping..."
    sleep 2
done

exit 0