Realtime sync across multiple computers

What software can I use to synchronize files that detects changes on each of my computers and syncs continuously with an always-on server? I'm looking for:

  • Running as a service on the server and the clients
  • Realtime change detection
  • Delta sync (ID3 tag editing shouldn't result in the whole file being transfered, for example)

I have a VPN, so local network only and unencrypted traffic is OK. Services that require cloud storage like DropBox are out since I'm maintaining my own server.

EDIT: I've been using the excellent Cubby (in beta at https://www.cubby.com/). No need for a VPN, seems almost like the holy grail of sync. Online storage is optional, so you have uninhibited direct sync without it.


Solution 1:

there are plenty of rsync solutions for windows. rsync is a software application and network protocol for Unix-like and Windows systems which synchronizes files and directories from one location to another while minimizing data transfer using delta encoding when appropriate. An important feature of rsync not found in most similar programs/protocols is that the mirroring takes place with only one transmission in each direction. rsync can copy or display directory contents and copy files, optionally using compression and recursion.

Solution 2:

Microsoft has the Distributed File System Technology (DFS) that exists for syncing between servers, but, I have been searching for ages and not found a good solution that works as flawlessly as Dropbox or similar technologies for client computers.

Solution 3:

The free BestSync utility seems to do what you ask for.

Other possibilities are :

DSynchronize (scroll down to reach)
SYNCING.NET
BlueFish File Mirror
Dropbox : Not only does it sync files in real time, it stores copies and past versions online too.

Solution 4:

If you're looking for a native windows solution, that requires no additional software, you can use "offline files".
From each computer you simply access the folders you need directly on the server, only you turn on the feature "make available offline" for those folders, which will make windows keep a copy of them locally on each computer.
You can even change the location windows keeps these folders at.

Solution 5:

I believe Beyond Sync is the tool you are looking for. It isn't free (first 30 days are) but does run as a service and does realtime sync across networks, external devices, etc.