rsync - Mar 2006 - how to distinguish local add and remote delete?

hi,all, I have a question about how to distinguish local add and remote delete?
 
hope to get answer from any of you, thank you in advanced.
 
how to distinguish local add and remote delete:
Local is machine A, Rsync client, remote is machine B, Rsync server.
 
In our application, A and B are load balance and have same import.
 
file changes may happend in machin A or machine B.
 
So each time, A first get the changes from machine B, then push the changes to
machine B.
Or the reverse order.
 
my question is: if now machine B delete a file (file_delete_1.txt) and A add a
file (file_add_1.txt)
 
when A get the changes from machine B, it find that both file
"file_delete_1.txt" and "file_add_1.txt" are exist in
machine A and NOT in machine B,
so it think machine B formerly have these two file and now they were all
deleted!!!!! so machine A also delete the files "file_delete_1.txt"
and "file_add_1.txt".
 
How to avoid this situation?
 
If Rsyanc can not handle this situation, is their any other solution for it ?
 
thank you very much.
 
 
 
 
Best Regards
---------------------------------------------
yhhuang »ÆÓ»Ô
Server Dept.
TeleNav Shanghai Inc.
Tel:(21)6337 2220 ext 8651
www.telenav.com <http://www.telenav.com/> 
 
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On Mon, Mar 06, 2006 at 10:49:55AM +0800, Huang, YongHui
wrote:
> I have a question about how to distinguish local add and remote delete?
I just added this info to rsync's "resources" webpage:

  If you need a 2-way synchronization because both ends of the connection
  may be changing files, you may want to either look into a tool designed
  to do this (e.g. unison), or you may with to use an external wrapper for
  rsync that keeps extra data about what was in the last transfer so that
  it can figure out if a file is new or deleted (e.g. drsync).

    http://freshmeat.net/projects/unison/
    http://freshmeat.net/projects/drsync/

..wayne..