I didn't post this question at Slackware forum because some years ago, I posted a question on it, and, as some members sough that I was a Salix user and not a Slackware one, they said very clearly that I was not welcome.
Apart from people more or less polite, I've realized that the problem is not solved upgrading rsync. I downloaded version 3.2.6 and installed it trough "heroic" way (./configure, make...) and the issue remained, confirming Gapan's post. At the other hand, I could see that Luckybackup was not continued
, which was bad news for me.
For this reason I ask here: What software do you use or recommend for backups in your domestic installation?