nethserver-hotsync-save helped. No more error.
Thx a lot.
On my testinstallation backup module is not enabled, cause IMO it would be useless with hotsync. Right?
But rsync isn’t enabled with out backup? So hotsync should check wether rsync is up or not. Or at least it should be mentioned in the docs to check.
On the slave there a no modules installed. I read here:
That means in at least one hour, the slave should be a clone of the master, without installing a module by myself. Correct?
Thanks for helping also to @ctek