Network Sync

I recently got my hands on a shiny eee-PC for surprisingly little money. As I am travelling a fair bit at the moment, the opportunity was more than welcome. Now, mobility comes at a price and the price is called »multiple instances of files«. When the files in question are your PhD, it has the potential for a fantastic nightmare. Most people use dropbox to tackle this, but for one reason and another, I neither want to use that, nor ubuntu one. I have owncloud [see here], and after resolving some issues, the sync client works, but I still would like to keep more data in tune then I could possibly channel through my shared hosting plan. Unison (via ssh) seems the way to go.

Setting it up was a lot easier then I though. All it took was rbgeek’s exccellent article »File Synchronization Between Two Ubuntu Servers using Unison«.

Falko Timme’s article »Setting Up Unison File Synchronization Between Two Servers On Debian Squeeze« at howtoforge was also helpful. Another insightful article is Chris Lale’s »Synchronising laptop and desktop files using Unison« at Sourceforge.

One issue: normally your device gets an IP address automatically from your router. Unison settings depend on the IP address (for ssh connection), so if the IP address changes, Unison gets confused. Thus, we want a static IP address on the remote machine. Johnathan Hobson’s »Networking Tips and Tricks« are a good start. The settings that finally worked for me I got via chili555’s post on ubuntuforums. Using Netman’s GUI, I set:

I understand little, but what I do understand is this:

• »address« needs to be outside the router’s scope. Mine is configured to start at 10, so I picked 9.
• »gateway« simply seems to be the router’s ip-address
• »DNS-Servers«: no clue why 8.8.8.8, the other again seems to be router’s ip address

You can easily determine the router’s ip-address and the scope for auto DHCP from the router’s admin interface.

Other useful information and resources

SSH

• SSH Guide [help.ubuntu]
• SSH-Question [ubuntu forums]

Unison

• Unison
• Unison Howto
• Unison Tutorial [softprayog.in]

• Unison case involving SSH [Linuxjournal]

Alternatives

• Owncloud (see here for my setup)
• Sync files on Ubuntu oneWhich I wouldn’t like for it absolutely insists that it has to dwell in /home
• Share a folder via samba

[article started in January 2013; final, rewritten version from January 2014]