#!/bin/bash

# Fast backup using rsync

if [ $# -ne 2 ]; then
    echo "Usage: $(basename "$0") /dev/sdX backup"
    exit 1
fi

if [ "$(id -u)" -ne 0 ]; then
    echo "This script must be run as root."
    exit 1
fi

rsync_options="-auvP --delete"
device=$1
name=$2

# Note: `name` (nor `device`) should not contain spaces

cryptsetup open --type luks $device $name
if [ $? -ne 0 ]; then
    # bad device
    exit 1
fi
mount /dev/mapper/$name /mnt/$name
# TODO: stop backing up /var.  Backup is just for Postgres and Mediawiki.
# `/var` is used by too many applications.  Specialy pacman that clutters it
# with cached binaries.
rsync $rsync_options /var /mnt/$name        # <10G
rsync $rsync_options /home /mnt/$name       # <900G
rsync $rsync_options /etc /mnt/$name        # <20M
echo "Backup complete."
df -h
umount /mnt/$name
cryptsetup close $name

echo "All done.  Check \`$ lsblk\` before unplugging the storage device."