hello
I have some problem with syncing efficiency.
I need to do frequent syncs from local machine to some remote location.
Currently I use rsync with backup option. The problem is that it works too slow because of connection quality.
Even _no_single_file_ is changed it lasts for about minute with directory tree containing about 35MB in 800 files.

Since my needs are rather simple I had idea to write my own script employing find command and some logging, but later I have realized that it could be only a question of options passed to rsync or a question of using some different existing tool.

I don't need to worry about files contents, modification dates or even files existence at remote location. I just need to copy all files modified locally after previous sync but first backup their remote versions (if they exist) in backup dir at remote location.
In other words: the decision which files to sync can be made locally without any references to destination directory tree state. But I need to know a list of modified files since last sync.

Both machines running linux. I can mount remote location into my local filesystem.
Efficiency is priority. I would like to shorten the operation time from minute to seconds.

Any idea how to do it?

regards for all

Before searching other solutions, did you try your rsync command with the -v (verbose) option set, just to check what it really does?