Thanks for the comments! The link to Phil’s blog was an interesting read. I hadn’t heard of lsyncd before and it offers some interesting prospects, like syncing some directories of my PC at work with my server at home. At the moment I’m using unison for that, but since the computer and my server are always connected lsyncd seems easier as it does everything in the background (I guess I’ll keep using unison on my laptop, because it’s not always connected).

Using lsyncd/lipsync for my backups to the NAS won’t be a good idea, however, because that would mean that every change (including erroneous deletes etc.) will immediately be mirrored to the NAS. No real problem for a dropbox-like situation, but the idea of backups is that they change less fast than the data you’re working on, so you can undo any mistakes you made.

Going back to your problem of installing lipsync on your computer, I took a quick look at the install script and it seems to ask only a few questions:

• Server name or IP: this should be the domain name or IP address of your NAS
• Server SSH port: this is 22 on the NAS
• Server and client user name: up to you to decide, but it looks like they have to be the same on both your PC and the NAS
• The directory to be synced on the client
• The directory to be synced on the server (NAS)

After getting the answers to these questions lipsync will set up SSH key, copy it to the NAS and finish the configuration of lsyncd, a first synchronisation, etc.

If it isn’t working for you, could you tell me where things go wrong (error messages, etc.)?

Good luck and thanks a lot!

Both my provider and the provider of my sister (Where the NAS is located) don’t force reconneting, so I don’t have any real experiences with that. My guess would be that if an rsync transmission is disconnected it will end the transfer. If the disconnection and the reconnection happen fast enough (I’d say on the order of a few seconds) everything might be OK, but I wouldn’t count on that for my backups.

Since rsync (with the -P option) can continue transferring partially transferred files, you could use that to run the interupted backup again so that it can complete. I guess that the return value of rsync will be non-zero it the transfer is interrupted (or if anything else happens). You could test for that return value in the script as you propose and keep rerunning the rsync command (with -P) until it finishes without problems.
This is more or less what I propose (I didn’t test it), replace the rsync line in the script with:

retval=1
while [ $retval -ne 0 ]; do
   rsync $OPTIONS $EXCLUSIONS $SRC $DEST
   retval=$0
done

Good luck!

The two Phil links that would be of interest are:

1. His Blog that describes “HOW TO build your own open source Dropbox clone”
http://fak3r.com/howto-build-your-own-open-source-dropbox-clone/

2. His related lipsync open source project that creates an easy to use installer (here’s where I don’t know what values are relevant to DS211J when it is set up as an rsync server).
https://github.com/philcryer/lipsync

Thanks again for sharing your skill with the world.

From the U.S.,
Nick

How does rsync handle interruptions of the internet connection between the two Diskstations?

At least in Germany, your router is forced to disconnect from the internet once every 24 h. So when I backup a bigger chunk of data, rsync won’t be finished with the job before a forced disconnection takes place. Moreover, the router has to refresh its domain as its IP changes after each reconnection (via DynDNS in my case). Does this lead to additional trouble?

Can rsync handel this issue itself or do I have to add a loop into the script that restarts rsync after a specific error code is reported?

I would be very grateful for any comment on that!