Rsync/SSH online backup cronjob for RPi

1. Create and secure keys folder for root

# mkdir /root/.keys /root/.keys/storage
# chmod 600 /root/.keys
# chmod 600 /root/.keys/storage

2. Obtain and secure storage SSH client key 'id_dsa' in this folder

# chmod 600 /root/.keys/storage/id_dsa

3. Save following as rsync.sh

#!/bin/bash

# run as root

   APPDIR="${BASH_SOURCE%/*}"
   LOGFMT="%t %i %b %n%L"

# remove following comment if testing 

   DRYRUN=""
   #DRYRUN=-n

   SKIPDIRS="$APPDIR/skipdirs"    

   SSH=/usr/bin/ssh
   KEY=/root/.keys/storage/id_dsa
   RUSER=john
   RHOST=storage.lan

   function run_rsync {
      /usr/bin/rsync $DRYRUN -axHv --exclude-from=$SKIPDIRS --delete-during --out-format="$LOGFMT" -e "$SSH -i $KEY" $2 $RUSER@$RHOST:$1
   }

   echo -e "\n========================================="
   echo "RSYNC push : Started `date`"

   run_rsync /c/backup/rpi /

   echo "RSYNC push : Finished `date`"

4. Save following as skipdirs

# directories to exclude from backup

# skip in-memory interfaces to the kernal
/proc/*
/sys/*

# skip dev, same reason
/dev/*

# skip hard links / mount points
/boot/*
/tmp/*
/run/*
/mnt/*
/media/*

# skip application generated stuff
/var/www/mrtg/*

# skip logs & temp files
/var/log/*
/var/swap

5. Save following as rsync in /etc/cron.d

0 */8 * * * root /home/user/rsync.sh 2>&1 >> /var/log/cron/rsync/rsync.log