ftp:// error

Matt McCutchen hashproduct at verizon.net
Fri Dec 2 21:20:48 GMT 2005

On Fri, 2005-12-02 at 17:41 +0000, Manuel López-Ibáñez wrote:
> I am sorry, the rsync algorithm needs to execute rsync on the server. 
> Since ftp does not allow executing remote programs (as ssh does), even 
> if there exists a rsync executable installed in the server and you have 
> permission to execute it, using ftp you cannot execute it. So your 
> command won't work and it will never be because it is impossible to 
> implement it by the very differences of what rsync does (executing a 
> remote rsync program) and how ftp works (just download files).

In my opinion, that's a perfect explanation.

However, Marten is probably far from the only person who would love to
use rsync over an FTP connection.  Its flexibility has to surpass that
of just about every tool that does support FTP.  Yet there is the
problem of not being able to run rsync on the other side.

So let me suggest that someone make a hacked version of rsync that
accesses a filesystem over FTP instead of a local filesystem.  This
shouldn't be too difficult since rsync already has a filesystem
abstraction layer (do_stat, do_open, etc.).  Then, one could do rsync
over FTP by running both processes on the local machine.  Of course, the
send-the-differences algorithm would not be useful, but all of the other
features would work.

If someone has written a stable FTP virtual filesystem for FUSE or
similar, one could achieve the same effect by doing a "local" rsync
involving the virtual filesystem.  Incidentally, a while ago on the
list, people were doing essentially this but over NFS and wondered why
the send-the-differences algorithm didn't seem to be reducing I/O.
Matt McCutchen, ``hashproduct''
hashproduct at verizon.net -- http://hashproduct.metaesthetics.net/

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