Quite a few months back, I experimented with BitTorrent Sync, but I found that I didn't have a practical use for it back then.
Now however, I have thought of something that I'd like to use it for but was wondering whether there were any open source alternatives around that I should be checking out first.
I have a couple of small files that I would like to backup to a range of different systems, running on windows, Debian, Arch and potentially Android. I'd like to keep the files somewhat secure (already encrypted), so I'd like to keep them out of any traditional cloud based services.
Heard of Syncthing? I haven't used used it personally, but I know @wendell has mentioned it on a couple of occasions.
I suggest looking at this thread which talks about must have linux software - torrent clients included
QBittorrent and Transmisson are really promising tho.
I've tried BitTorrent sync, but always find bit torrent sort of processor heavy to run constantly on my main machine. Same with Dropbox.
I switched to Owncloud about 8 months ago, and sync like 7 machines, without any issues.
It runs on-top of NGINX (or Apache), and PHP-FPM, so it's like impossible to saturate GBE, but it's been rock solid stable, and relatively light weight in my experience. Also, it tracks deletion, or file changes.
The Owncloud app for has been getting significantly better, and web interface can trickle sync basically unlimited external sources, like S3, or Dropbox.
I've heard / read syncthing is not as mature as Owncloud. While Owncloud addon-apps have a long way to go, the basic app gets 8.5 out of 10 IMO.
I use Syncthing between Ubuntu, Windows and Android and have been very happy with it for a long time, even since early days it's been reliable, certainly in the last few months I don't ever remember missing any files.
The only issue I had was with Maildir's and symlinks in Windows, where the file system doesn't support them.
-Syncthing-GTK on *nix with a GUI (http://www.webupd8.org/2014/09/syncthing-gui-gtk3-python-gui-ubuntu-ppa.html )
-Synctrayzor on Windows (https://github.com/canton7/SyncTrayzor/releases)
-And there is an android GUI on F-Droid (probably Google too)
Also found having an always on node made the whole thing better, allowing 4 devices to keep things in sync without needing to be on together, you get this by definition with ownCloud, which I abandoned because it was too slow at getting updates around the systems (YMMV, I'm sure it's fine overall)
You can also set Trash Can mode for deleted files (good for the allways-on node), with no expiry, as a safety net.