#!/bin/bash
#set -e

NUM_TO_KEEP=2
NICE_LEVEL='10'
TGT="/opt/backups"

PATH=/sbin:${PATH}

LVMS=$(/sbin/lvs | grep 'wi' | awk {'print $2 ":" $1'} | grep -v orig)

echo "$(date) - Starting..."
for LVM in ${LVMS}; do
   VG=$(echo ${LVM} | cut -f1 -d':')
   LV=$(echo ${LVM} | cut -f2 -d':')
   
   case $LV in
      snap)
         ;;
      *)
         echo "Working with ${VG} ${LV}..."

         # ensure that the snapshot volume is gone
         lvremove -f /dev/${VG}/snap > /dev/null 2>&1

         # create a new snapshot volume
         lvcreate -L10G -s -n snap /dev/${VG}/${LV}
         sleep 2

         # perform the actual backup
         DST="${TGT}/${VG}-${LV}-$(date +%Y%m%d).img.gz"
	      if [ ! -f ${DST}.done ]; then
            rm -f ${DST}
            nice -n ${NICE_LEVEL} dd bs=5M if=/dev/${VG}/snap | \
            nice -n ${NICE_LEVEL}  gzip --rsyncable > ${DST} && \
            touch ${DST}.done
      	fi

         # clean up after ourselves
         lvremove -f /dev/${VG}/snap > /dev/null 2>&1
         sleep 2
         
         if [ -f ${DST}.done ]; then
            # need to remove old backup instances
            PATTERN="${VG}-${LV}-[0-9][0-9][0-9][0-9]"
            PATTERN="${PATTERN}[0-9][0-9][0-9][0-9].img.gz"
            I=0
            for FILE in $(ls -t ${TGT}/${PATTERN}); do
               if [ "${I}" -lt ${NUM_TO_KEEP} ]; then
                  echo "Keeping ${FILE}"
               else
                  echo "Removing ${FILE}"
                  rm -f ${FILE}
                  rm -f ${FILE}.done
               fi
               I=$((I+1))
            done

            # need to update the hard link folder
            LINK="${TGT}/link/${VG}-${LV}.img.gz"
            rm -f ${LINK}
            ln ${DST} ${LINK}
         fi
         ;;
   esac
done
echo "$(date) - Finished..."