#!/bin/bash
set +e
# these processes keep files open that prevent us from remounting ro
killall dhclient
service mysql stop
service apache2 stop
service rsyslog stop


#e4defrag /
mount -o remount,ro / && zerofree -v /dev/sda1; sudo mount -o remount,rw /

#e4defrag /data/
mount -o remount,ro /data && zerofree -v /dev/sdb1
# if the first one did work, try this
mount -o ro /data && zerofree -v /dev/sdb1
mount -o remount,rw /data
