Editing Backup Linux desktop data using rsync

__TOC__

Linux servers and desktops can be backed up using the rsync protocol which is a core component of every Linux system. For and introduction check the [[wikipedia:rsync|rsync article]] on [[wikipedia:Main|Wikipedia]]. [http://www.samba.org/ftp/rsync/rsync.html The official documentation] can be found on the Samba website. Rsync is an efficient protocol only sending changes. rsync does not encrypt transmissions, so a remote shell like SSH or RSH should be used in public network. There are a number of [http://everythinglinux.org/rsync/|Rsync Tutorials] available ([http://www.mikerubel.org/computers/rsync_snapshots/ here], [http://www.unixtutorial.org/2008/09/how-to-synchronize-directories-with-rsync/ here] or [http://www.google.com/search?q=rsync+tutorial here]). This page describes the steps to setup rsync backup from a Linux machine to a Synology DiskStation.

<b>ToDo</b>:Currently the article is a stub which needs extension.

==What to choose: native rsync or rsync via SSH/RSH?==
Depending on your needs these are the decision criteria:
* Speed
* Security
* Access control
<b>ToDo</b>: Elaborate

==Setting up Synology for rsync==
To enable backup via rsync the rsync deamon on the Synology needs to be activated and Sync targets need to be defined.

<b>Activating rsync</b><br />
Start your Synology DiskStation Manager. Go to Backup - Network Backup Service and check the box "Enable network backup service". Click OK - that's all.

<b>Creating rsync targets</b><br />
You need to edit the file <b>/etc/rsyncd.conf</b>. You can do that either by opening an SSH session into the DiskStation or using the [http://www.mertymade.com/syno/#cfe Config File Editor] Third party application. To use it you need to first edit the config File editor config itself and add the line /etc/rsyncd.conf (It seems you have to create the file before the Config File Editor will pick it up). You also might need a file /etc/rsyncd.secrets for users to use rsync connections

<b>Sample file content</b> (see also the [http://www.samba.org/ftp/rsync/rsyncd.conf.html full documentation])<br />
<b>ToDo</b>: Add file content here and add explanations to the various entries

==Setting up Synology for rsync via SSH/RSH==
When using ssh no rsync deamon is used on the DiskStation. However you need to have a valid public / private key pair, so the DiskStation can recognize the Linux machine. Follow the following steps ([http://troy.jdmz.net/rsync/index.html adopted from here])

<b>Generate they key pair</b>

<code>
mkdir ~/.sshkeys<br /> 
cd ~/.sshkeys<br /> 
ssh-keygen -t dsa -b 1024 -f ~/.sshkeys/diskstation-rsync-key 
</code>

Generating public/private dsa key pair. 
Enter passphrase (empty for no passphrase): [press enter here]<br /> 
Enter same passphrase again: [press enter here]<br /> 
Your identification has been saved in ... diskstation-rsync-key. <br />
Your public key has been saved in  ... diskstation-rsync-key. <br />
( where  ... stands for your directory )<br />
<code>
chmod 600 diskstation-rsync-key
</code>

<b>Transfer the keys</b><br />
Use your file manager (e.g. Nautilus) to navigate to <code>[YourUserName]@smb://diskstation/home/</code><br />
Create a directory <code>.ssh</code> and copy diskstation-rsync-key.pub there.<br />
Now open a SSH connection to the diskstation to continue:<br />
<code>
ssh user@diskstation [Enter password here]<br />
cd /volume1/homes/[YourUserName]/.ssh<br />
ls -l
</code>

If there is already a "authorized_keys" file you skip the first line of the following code:

<code>
touch authorized_keys<br />
cat diskstation-rsync-key.pub >> authorized_keys<br />
rm diskstation-rsync-key.pub<br />
chmod 600 authorized_keys<br />
</code>
You can restrict the use of this key for specific commands or IP addresses ([http://troy.jdmz.net/rsync/index.html see here]).<br />
Exit from the SSH session. Now you are ready to test the keys with the following command:<br />
<code>
ssh -i ~/.sshkeys/diskstation-rsync-key [YourUserName]@diskstation
</code><br />
If you get a ssh session without a password prompt the ssh connection using your new keys works.<br />

<b>Sample backup command</b><br />
<code>
rsync --recursive --copy-links --times --verbose  --progress -e "ssh -i ~/.sshkeys/diskstation-rsync-key" \<br />
/home/[localusername] [YourUserName]@diskstation/volume1/homes/[YourUserName]/backup
</code><br />
<b>TODO:</b> Explain a little more

==Backing up your Linux workstation using rsync==
<b>ToDo</b>: Elaborate

==GUI Tools using rsync for backup==
[[Wikipedia:FlyBack|Flyback]] rSync tool modeled after TimeMachine ([http://code.google.com/p/flyback/ Flyback on Google code])
<br />[http://qtdtools.doering-thomas.de/page.php?seite=0&sub=0&lang=en QTDSync]
<br />[http://gadmintools.flippedweb.com/index.php?option=com_content&task=view&id=51&Itemid=38 GAdmin tool for rsync]
<br /><b>ToDo</b>: complete the list of Linux GUI applications using rsync.