#!/bin/bash
((verbose = 0))
((iterations = 10))
((delay = 1))
progress=''
tmpDir='/tmp/io-use'
server[1]='MDS'
server[2]='OSS'

while [[ "X" != "X$1" ]]
 do
   if [[ "-v" == "$1" ]]
    then 
      ((verbose = 1))
      progress='.'
   elif [[ "-i" == "$1" ]]
    then 
      shift
      x="$1"
      ((iterations = x))
   elif [[ "-d" == "$1" ]]
    then 
      shift
      x="$1"
      ((delay = x))
    else
      echo "Usage: $0 [-v] [-c #]"
      echo "  -v is verbose"
      echo "  -i # performs # iterations (default is 10)"
      echo "  -d # delays # time between iterations (default is 1 second)"
      exit
    fi
   shift
 done

if ((1 == verbose))
 then
   echo "Options:"
   echo "  Provide verbose feedback"
   echo "  ${iterations} iterations to be performed"
   echo "  ${delay} second(s) between each iteration"
   echo " "
 fi
COMMANDS=()
# if we have an MDT mount
kind=$(mount | grep -i 'mdt')
if [[ 'X' != "X${kind}" ]]
 then
   char[1]='m'
   procFile='/proc/fs/lustre/mds/MDS/mdt/req_history'
   if [[ -f ${procFile} ]]
    then
      COMMANDS[1]="cat ${procFile}"
    else
      COMMANDS[1]="lctl get_param mds.MDS.mdt.req_history"
    fi
 fi

# if we have an OST mount
kind=$(mount | grep -i 'ost')
if [[ 'X' != "X${kind}" ]]
 then
   char[2]='o'
   procFile='/proc/fs/lustre/ost/OSS/ost_io/req_history'
   if [[ -f ${procFile} ]]
    then
      COMMANDS[2]="cat ${procFile}"
    else
      COMMANDS[2]="lctl get_param ost.OSS.ost_io.req_history"
    fi
fi

# set count to parameter 1 if passed
if [[ "X" == "X$1" ]]
 then 
    ((count = 10))
 else
    count="$1"
 fi    

# big command loop
for idx in "${!COMMANDS[@]}"
 do
# get rid of existing DIR and its contents
   if [[ -d ${tmpDir} ]]
    then
      rm -rf ${tmpDir}
    fi
   mkdir ${tmpDir}
   cd ${tmpDir}
   # touch an empty file so that if no I/O is going on, we do not get a grep error
   touch dummy
   
   if ((1 == verbose))
    then
      echo "using: ${COMMANDS[${idx}]}"
    fi
  ((count = iterations)) 
   while ((0 < count))
    do
       ${COMMANDS[${idx}]} | grep -v req_history | grep -v Complete | awk -F':' '{print $3}' | sed 's/12345-//' | awk -F'@' '{print $1}' | while read num
        do 
           name=$(grep ${num} /etc/hosts | head -1 | awk '{print $2}')
           if [[ 'X' == "X${name}" ]]
            then
              name="${num}"
            fi
   
           echo -n ${char[${idx}]} >> ${name}
        done
       ((count = count - 1))
       echo -n ${progress}
       sleep ${delay}
    done
   if ((1 == verbose))
    then
      echo " "
    fi
   idle=$(ls -1 | wc -l)
   if ((1 == idle))
    then
      echo "${server[${idx}]} idle"
    else
      grep -H ${char[${idx}]} *
    fi
   cd - >/dev/null
   rm -rf ${tmpDir}
 done