fsbench

#!/bin/bash

# macOS doesn't have gnu date so no +%N also dd wants m instead of M for buffer size
# about the same with FreeBSD
# patches welcome
#
# https://www.thegeekdiary.com/how-to-clear-the-buffer-pagecache-disk-cache-under-linux/

# check if called binaries are available
for a in uname date bc seq sync dd file awk tail grep shuf; do
    hash $a >/dev/null
    if [ ! $? -eq 0 ]; then
	echo $a not found
	exit 1
    fi
done

trap ctrl_c INT

# catch ctrl-c
function ctrl_c() {
    echo -e "\rCleaning up..."
    if [ -d _fsbench ]; then
	rm -rf _fsbench
    fi
    exit 0
}

# does the user want to test with something else than up to 50 mb files?
if [ "$#" -ne 1 ]; then
    num=50
else
    num=$1
    if ! expr $num + 0 >/dev/null 2>&1; then
	echo Syntax error: need a number.
	exit 1
    fi
fi

# check if there's enough diskspace, compare value above with num
freemb=`df -m . | tail -1 | awk '{print $4}'`
if [ $num -gt $freemb ]; then
    echo $num MB diskspace needed, but only $freemb MB found.
    exit 1
fi

totalmb=0
for a in `seq -f "%04.0f" 1 $num`; do
    totalmb=`echo ${totalmb}+${a}|bc`
done

if [ `uname` = Linux ]; then
    if [ 0 -eq `id -u` ]; then
        # drop filesystem caches
        echo 3 > /proc/sys/vm/drop_caches
	echo "Filesystem:" `file -bLs $(df -h . | tail -1 | awk '{print $1}')`
    fi
fi

sync
start=`date +%s.%N`

if [ -d _fsbench ]; then
    rm -rf _fsbench
fi
mkdir _fsbench 2>/dev/null
if [ ! $? -eq 0 ]; then
    echo "Can't create temporary directory"
    exit 1
fi
mb=0
for a in `seq -f "%04.0f" 1 $num | shuf`; do
    percent=`echo ${mb}*100/${totalmb}|bc`
    mb=`echo ${mb}+${a}|bc`
    echo -ne "${percent}% (${mb} MB)"
    dd if=/dev/zero of=_fsbench/$a bs=${a}M count=1 2>/dev/null
    rm _fsbench/$a
    mkdir _fsbench/$a
    echo -ne "     \r"
done
echo
rm -rf _fsbench

sync
end=`date +%s.%N`

# print results
echo "Time used in seconds to create $num files of 1 to $num MB size, and $num"
echo -n "directories, then removing them all: "
t=`echo $end - $start | bc`
ts=`echo ${totalmb}/${t}|bc`
echo $t
echo "Making a total read/write of: $ts MB/s"