Quick and dirty backups using rdiff-backup

local-backup

#!/bin/sh
# Quick and dirty backups using rdiff-backup
# Usage: /path/to/local-backup --source /mnt/source \
#                              --destination /mnt/source-mirror \
#                              --lock-file /var/lock/local-backup/job-name \
#                              --age 4W

eval set -- "$(getopt -o "adls:" --long "age:,destination:,lock-file:,mount-point:,source:" -- "$@")"
while true; do
    case "$1" in
        -a|--age        ) MAXAGE="$2"       ; shift 2 ;;
        -d|--destination) TARGETMNTDIR="$2" ; shift 2 ;;
        -l|--lock-file  ) LOCKFILE="$2"     ; shift 2 ;;
        -s|--source     ) SRCDIR="$2"       ; shift 2 ;;
        * ) break                                     ;;
    esac
done

TARGETDIR="$TARGETMNTDIR/backup"
TARGETRESERVED="$TARGETMNTDIR/reserved"

if [ "$USER" != "root" ]; then
    echo "This script must be executed as root; aborting!" >&2
    exit
fi

if [ -f "$LOCKFILE" ]; then
    echo "Lock file detected; aborting" >&2
    echo "This usually means the previous job crashed. Ensure no jobs are active, remove the lock file and retry." >&2
    exit
fi

if ! rdiff-backup --version &> /dev/null; then
    echo "rdiff-backup is not on PATH; aborting" >&2
    echo "Is rdiff-backup installed?" >&2
    exit
fi

touch "$LOCKFILE"

if [ "$(ls -A $TARGETMNTDIR)" ]; then
    echo "$TARGETMNTDIR contains files; refusing to proceed mounting." >&2
    echo "Maybe a prior backup run left the target device mounted?" >&2
    exit
fi
mount "$TARGETMNTDIR"
if ! mountpoint -q "$TARGETMNTDIR"; then
    echo "Failed to mount $TARGETMNTDIR; aborting" >&2
    echo "Does the mount point appear in /etc/fstab?" >&2
    exit
fi

if [ ! -f "$TARGETRESERVED" ]; then
    echo -n "Reserve file not present, writing... "
    dd if=/dev/zero of="$TARGETRESERVED" bs=1M count=1000
    echo "done."
fi

mkdir -p "$TARGETDIR"

echo "Removing older files..."
rdiff-backup -v 9 --remove-older-than "$MAXAGE" --force "$TARGETDIR"
echo "done."

echo "Performing the backup..."
rdiff-backup -v 9 "$SRCDIR" "$TARGETDIR"
echo "done."

umount "$TARGETMNTDIR"
if mountpoint -q "$TARGETMNTDIR"; then
    echo "Attempted to unmount $TARGETMNTDIR butit still appears to be a mountpount!" >&2
    echo "Refusing to remove the directory automatically." >&2
    exit
fi

rm -f "$LOCKFILE"