netbsdnoob I'm very confused, because I've ran
sysupgrade auto several times and it always asked me which configuration files to keep/overwrite/merge. Did you mess with sysupgrade.conf too much?
Also, sysupgrade never touched my /home. Mainly, I think, because /home is not part of the sets and the contents are entirely user-created, with some dotfiles copied over from /etc/skel at account creation time. So it has no reason to touch it, really.
Now I'm curious as to what you did. Can you please write down the exact steps you took? Both before and after you ran sysupgrade.
netbsdnoob In addition, when i run sysupgrade auto again, why it does not detect that I am already on the latest installation and don't need to upgrade?
Sysupgrade is not a package manager. Rather, it's a script that downloads the sets (archives containing the base NetBSD system) and extracts them, automating what was a boring manual procedure before.
This is a fundamental difference between Linux and BSDs. Linux is a collection of packages, and you update that with a package manager that checks whether every package on the system has a newer version. BSDs are split between the base system installed from sets, and additional software installed on top of that from ports (pkgsrc in NetBSD's case). Because it's split like that, you can update the base system simply by extracting updated sets into / which overwrites the old binaries/libraries/etc.
Furthermore, the base system is usually available in three different forms:
RELEASE is the formal release and doesn't change after it's released (e.g. 9.0, 9.1).
STABLE is the branch with continuous fixes and improvements to the formal release. A new minor release is eventually created from this (e.g. 9.1 was created from 9_STABLE).
CURRENT is the ever-rolling branch with all the new commits. A new major release is eventually created from this.
The sets in "NetBSD-daily/netbsd-9/latest" are the daily builds of STABLE branch of NetBSD 9, so updating once a week with sysupgrade is approximately like updating a Linux distro.
Of course, pkgsrc has to be updated separately:
pkgin up && pkgin ug if you installed from binary packages.