No possible incremental backup ?

[L. AHMADI]

Hi,

I use rsync to mirror users directories from a Dec Unix box to a Linux
box. Rsync has a nice feature : the remote-update protocol to make
transfer very fast. Unfortunately, I discover that  the size of
directories are always 4096 in Linux (?) and are of different sizes in
DecUnix. So, even with no changes in directories, rsync can't skip any
file to transfer because of the mentioned problem .
I see any rsync option which can help me.

Any idea ?