A rsync incremental backup script which backs all data on a non-bootable partition. This script doesn't delete anything on destination/target disk.

.backupignore

.Spotlight-*/
.DocumentRevisions-*/
.MobileBackups/
.Trashes
/afs/*
/automount/*
/cores/*
/dev/*
/Network/*
/private/tmp/*
/private/var/run/*
/private/var/spool/postfix/*
/private/var/vm/*
/Previous Systems.localized
/tmp/*
/Volumes/*
*/.Trash

rsync_incremental_backup.sh

#!/bin/bash

# Source Script: https://github.com/necolas/dotfiles/blob/master/bin/backup 
# Original Author: Nicolas Gallagher (http://nicolasgallagher.com)

# Modified by: Abdul Qabiz
# The script has been modified to do incremental data (non bootable) backup.
# The script doesn't delete anything on destination ($DST).

# Disc backup script
# Requires rsync 3

# Ask for the administrator password upfront
sudo -v

# IMPORTANT: Make sure you update the `DST` variable to match the name of the
# destination backup drive

DST="/Volumes/MacintoshHD_Archive/"
SRC="/"
EXCLUDE="$HOME/.backupignore"

PROG=$0

# --acls                   update the destination ACLs to be the same as the source ACLs
# --archive                turn on archive mode (recursive copy + retain attributes)
# --delete                 delete any files that have been deleted locally
# --delete-excluded        delete any files (on DST) that are part of the list of excluded files
# --exclude-from           reference a list of files to exclude
# --hard-links             preserve hard-links
# --one-file-system        don't cross device boundaries (ignore mounted volumes)
# --sparse                 handle sparse files efficiently
# --verbose                increase verbosity
# --xattrs                 update the remote extended attributes to be the same as the local ones

if [ ! -r "$SRC" ]; then
    logger -t $PROG "Source $SRC not readable - Cannot start the sync process"
    exit;
fi

if [ ! -w "$DST" ]; then
    logger -t $PROG "Destination $DST not writeable - Cannot start the sync process"
    exit;
fi

logger -t $PROG "Start rsync"

sudo rsync --acls \
           --archive \
           --exclude-from=$EXCLUDE \
           --hard-links \
           --one-file-system \
           --sparse \
           --verbose \
           --xattrs \
           "$SRC" "$DST"

logger -t $PROG "End rsync"

exit 0