dddiskspeedtest.bash

#!/bin/bash
#
# Author: Peter Maloney
# License: GPLv2
#
# Tests the read speed at random spots on the disk (does not use the entire surface, just many points) to find if there are some slow spots.
# To make it scan the whole disk, lower the "increment" variable to a number greater than count.
#
# Usage:
#   $0 sdb,sdc
# or
#   $0 sdb,sdc mylog

# ========================
# Command Line Input
# ========================

# Comma separated device names without /dev/
# eg. sdb,sdc
disks="$1"

# Optional. The prefix for the log file. Default: "dddst"
# eg. A value of "mylog" would mean disk sda gets stored in mylog-sda.csv
logFilePrefix="$2"


# ========================
# Constants
# ========================

defaultLogFilePrefix=dddst
# the number of blocks to seek (including the $count read previously) for the next read
increment=1000
# the count of blocks to read
count=20
# NOTE: changing this means the totalMiB won't work... unsupported
bs=1M
# how many times to read the same spot for an average
avg=1

# ========================
# Command line handling
# ========================

if [ -z "$logFilePrefix" ]; then
    logFilePrefix=dddst
fi

# ========================
# Functions
# ========================

finddisksize() {
    disk="$1"
    parted /dev/${disk} unit B print | grep Disk | egrep -o "[0-9]+"
}

testdisk() {
    IFS=','
    for disk in ${disks}; do
        echo "${disk}"
        logFile="${logFilePrefix}-${disk}.csv"
        logFilePercent="${logFilePrefix}-${disk}-percent.csv"
        rm ${logFile} 2>&1

        totalBytes=$(finddisksize $disk)
        totalMiB=$(($totalBytes/1024/1024))
        echo "Total size: $totalMiB B"

        skip=0
        while [ "${skip}" -le "$totalMiB" ]; do
            #NOTE: relies on result being in MB/s
            if [ "$avg" -ge 1 ]; then
                runCount=0
                speedSum=0

                while [ "$runCount" -lt "$avg" ]; do
                    speed1=$(dd if=/dev/${disk} of=/dev/null bs=${bs} count=${count} skip=${skip} iflag=direct 2>&1 \
                        | egrep -o "[0-9\.]+ MB/s" | egrep -o "[0-9\.]+")
                    if [ "$?" != 0 -o -z "$speed1" ]; then
                        break
                    fi
                    speedSum=$(echo "${speed1}+${speedSum}" | bc)
                    let runCount++
                done
                speed=$(echo "scale=1; ${speedSum}/$runCount" | bc)
            else
                speed=$(dd if=/dev/${disk} of=/dev/null bs=${bs} count=${count} skip=${skip} iflag=direct 2>&1 \
                    | egrep -o "[0-9\.]+ MB/s" | egrep -o "[0-9\.]+")
                if [ "$?" != 0 -o -z "$speed" ]; then
                    break
                fi
            fi

            progress=$(echo "scale=2; ${skip}/(${totalMiB}/100)" | bc)

            printf "%6.2f%% : skip = %7d, speed = %.1f MB/s\n" $progress $skip $speed
            echo "${skip},${speed}" >> ${logFile}
            echo "${progress},${speed}" >> ${logFilePercent}
            let skip+=${increment}
        done
    done
}

# ========================
# Main
# ========================

testdisk "$disks"