Installing rsync

When you want to use your SPP as network storage media to back up your data, rsync is tool of choice, especially if you use a wireless connection.

rsync offers incremental, compressed, ssh-secured, recursive synchronization of directories.

rsync is uni-directional. For bi-directional synchronization, you have to run rsync twice.

Visit the rsync homepage for further information about rsync.

Prerequisites
enable ssh access and configure it so that you can ssh to your SPP without entering a password.
 * download the rsync binary (statically linked) here: rsync.zip and unzip the file.

Installation
The network name of my SPP is "screenplay" which I prefer over using the IP address (192.168.1.1 in my network).

The following code snippets assume, that ssh is already enabled and configured for root (I already created a home directory for root (/root) and also a ssh-key-file (/root/.ssh/authorized_keys) to ease administration of my SPP).


 * re-mount your SPP disk to make it writable ("ssh -l root mount -o rw,remount /") if not already done.
 * copy rsync to your SPP ("scp rsync root@screenplay:/usr/bin/rsync")
 * log into your SPP and make the file executable ("ssh -l root screenplay chmod 755 /usr/bin/rsync")
 * check the installation by fetching a file from the SPP using rsync: "rsync root@screenplay:/etc/passwd passwd"

Configuration
I created a personal environment for every user to preserve file permissions, etc.
 * create the user accounts on the SPP ("ssh -l root screenplay adduser foobar")
 * create a home directory for every user ("ssh -l root screenplay mkdir -p /home/foobar")
 * create a backup directory for every user ("ssh -l root screenplay mkdir /tmp/hddmedia/foobar")
 * Please note: The dvdplayer application runs as root, so everybody can browse the files which are stored on in the backup directories. You might prefer to name your backup directory /tmp/hddmedia/.foobar rather than foobar to create a hidden directory which is ignored by dvdplayer application.


 * link the backup directory into the home directory of the user ("ssh -l root ln -s /tmp/hddmedia/foobar /home/foobar/foobar")
 * change the ownerschip of the new files to the user ("ssh -l root chown -R foobar.foobar /home/foobar /tmp/hddmedia/foobar")
 * every user has to generate his own ssh secret:
 * Generate a key ("ssh-keygen"). Answer all prompts with empty string to generate a password-less key.
 * Copy the public key to the SPP ("ssh screenplay mkdir .ssh", "ssh screenplay chmod 700 .ssh", "scp .ssh/.id_rsa.pub screenplay:.ssh/authorized_keys")

Operation
Now rsync is ready to use ("rsync -auvz /home/foobar/ screenplay:foobar").

Add a cron job to execute rsync on a regular basis (if your host speaks Unix, Linux, MacOSX,...)