added bash script for remote rsync/btrfs snapshot backups

see file header for usage details

bash/backup-remote.sh

@@ -0,0 +1,63 @@
+#!/bin/bash
+##
+ # Sync with remote server and create btrfs snapshots
+ #
+ # This scripts uses rsync to sync remote directories with a local copy
+ # After every successful sync a readonly btrfs snapshot of this copy is
+ # created
+ #
+ # This script requires root privileges! Consider using public key auth-
+ # entification with SSH and allow root logins only with a private key:
+ #
+ # On remote side:
+ #  echo "PermitRootLogin without-password" >> /etc/ssh/sshd_config:
+ #
+ # On local side:
+ #  sudo ssh-keygen
+ #  sudo cat /root/.ssh/id_dsa.pub | ssh user@remote 'cat >> /root/.ssh/authorized_keys'
+ #
+ # @copyright   2013 Steffen Vogel
+ # @license     http://www.gnu.org/licenses/gpl.txt GNU Public License
+ # @author      Steffen Vogel <info@steffenvogel.de>
+ # @link        http://www.steffenvogel.de
+ ##
+##
+ # This script is free software: you can redistribute it and/or modify
+ # it under the terms of the GNU General Public License as published by
+ # the Free Software Foundation, either version 3 of the License, or
+ # any later version.
+ #
+ # This script is distributed in the hope that it will be useful,
+ # but WITHOUT ANY WARRANTY; without even the implied warranty of
+ # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ # GNU General Public License for more details.
+ #
+ # You should have received a copy of the GNU General Public License
+ # along with this script. If not, see <http://www.gnu.org/licenses/>.
+ ##
+
+function usage {
+        echo "Usage: $(basename $0) REMOTE LOCAL"
+        echo
+        echo "   REMOTE  a rsync source path/server"
+	echo "   LOCAL   the local destination directory"
+        exit 1
+}
+
+set -e
+
+if [ $# -ne 2 ]; then
+        usage
+fi
+
+HOST=$1
+DIR=$2
+
+DATE=$(date +%F_%H-%M-%S)
+EXCLUDE=/dev,/proc,/sys,/tmp,/run,/mnt,/media,/lost+found
+
+# sync with remote
+rsync -aAX --delete root@$HOST:/ $DIR/latest --exclude={$EXCLUDE}
+
+# create new readonly snapshot
+btrfs subvolume snapshot -r $DIR/latest $DIR/$DATE