#!/bin/bash
intv="$1"

if [ -z $intv ]
then
    intv=5
fi

prevhits=0
prevmisses=0

i=0

while true
do

    stats=`cat /proc/spl/kstat/zfs/arcstats`
    hit=`echo "$stats"  | grep -w hits | awk '{ print $3}'`
    miss=`echo "$stats"  | grep -w misses | awk '{ print $3}'`


    hitrate=$(((hit-prevhits)/intv))
    missrate=$(((miss-prevmisses)/intv))

    prevhits=$hit
    prevmisses=$miss

    req=$((hitrate+missrate))

    if [ "$hitrate" != 0 ] && [ "$req" != 0 ]
    then
        hitper=`echo "scale=2; (($hitrate / $req) * 100)" | bc`
    else
        hitper=0
    fi

    if [ "$i" -gt 0 ]
    then
        echo "IOPs: $req | ARC cache hit ratio: $hitper % | Hitrate: $hitrate / Missrate: $missrate"
    else
        echo "Loading"
    fi

    ((i++))
    sleep $intv
done