Debian Votes To Reinstate Merged-/usr File Movement Moratorium

[intelfx]

The real question is, what is the reasoning for a splitted-usr? Back in the days, some people wanted to be able to mount /usr via NFS, but who does that anymore? Companies who want to distribute software on their local network with NFS can still do this in another path anyway.

Having a splitted-usr is just an unnecessary complexity. And I remember back in the 2000s seeing scripts that would fail because they expect awk to be in /usr/bin when it was in /bin Thank god we don't need to care about this anymore.

And by the way, the merged-usr idea came up a long time before systemd. You could say systemd accelerated the transition though.

In fact, merged-usr does not preclude NFS-mounted /usr. The only thing merged-usr does is that it gets rid of the / vs /usr split — because initramfs has took up this duty long ago.

To be more precise, here is the actual history lesson.

Originally, after the /usr had become a thing, the role of / was "early userspace". That is, / had used to contain binaries that are needed to mount /usr, and /usr had used to contain everything else. Thus, / had to be local, and /usr could be remote.

Unfortunately, this meant that distro maintainers were responsible for carefully putting everything that can be used for mounting /usr into /. This is bad for 2 reasons: 1) it clogged up / with stuff that you might not need, and 2) it limited you with the tools that the distro maintainers have decided to put into /. If your setup was complicated enough to exceed the tools made available in / by your distro maintainers, that meant you had to rebuild the affected software with a different prefix.

Nowadays the role of "early userspace" is served by an initramfs. An initramfs can be generated with precisely the required binaries and nothing else, and then it can be very tightly compressed, reducing local disk usage even more. Once this is done and once you have an initramfs with all the tools you need to mount your filesystems, there is no more need for any binaries in /. Case closed.