Unison (was Re: [plug] Fastest way to transfer files over Internet)

[James Devenish]

In message <1052710270.984.39.camel at vaio>
on Mon, May 12, 2003 at 11:31:10AM +0800, Ryan wrote:
> I've got various wrapper scripts around it to allow me to specify
> directories and users to synch etc. 

I have a collection of a dozen or so `profiles' that preserve my
synchronisation options and reduce the number of keystrokes
required on the command line.

> I've read some sites that mention this is normal for SMB
> synchronisations and that unison has to be running on the remote
> computer for the 'smart' stuff to work.

The problem is that SMB (and all Windows filesystems that the Unison
authors know of) doesn't provide low-level information that would let
Unison know whether a file has or has not changed between invocations.
Therefore, it has to analyse the content of files. It's not so much
whether you're running it on both computers or not (it works with NFS
mounts) but whether there is a safe way to detect changes.

> Is it possible to make unison on Debian talk to unison on NT so it can
> transfer more efficiently?

Three options come to mind:
 - overwrite NT with a POSIX-like operating system.
 - ask Unison to look only at directories where you know
   changes have occurred.
 - use the -fastcheck option :)

> All the playing on the Windows client I did several months ago seemed
> to suggest it can't 'listen' for another remote unison 'server' to
> kick it off, but I'll happily stand corrected.

Perhaps it needs UNIX daemons (e.g. Cygwin or something).