I/O load logging in CSV / Excel format

#!/bin/bash

# log-iowait.sh

# a script to log the I/O load,
# and store the output as CSV format, which can be opened directly in Excel

# Great for troubleshooting I/O related problems

# set this to run every minute in cron

logfile=/tmp/log-iowait.csv

# show timestamp + I/O wait statistic
# -d 1 3 = delay 1 second, run 3 times (first run are usually spiked)
echo "\"`date +%H%M`\",\"`iostat -d 1 3 -c | tail -n 6 | head -n 1 | cut -c 35-39`\"" >> $logfile