What is the "upgrade path" for an older system that has /usr split off? Will it just stop being bootable after upgrading?It just needs to use an initramfs. A standalone /usr without an initramfs IS ALREADY NOT SUPPORTED by systemd. This is not relevant for merged /usr.
What is the "upgrade path" for an older system that has /usr split off? Will it just stop being bootable after upgrading?It just needs to use an initramfs. A standalone /usr without an initramfs IS ALREADY NOT SUPPORTED by systemd. This is not relevant for merged /usr.
It is not supported *BUT* just works as expected on more than 20 machines I have access to, especially now that the debian systemd maintainers make sure systemd do not depend on libraries installed in /usr... Systemd shall make linux boot easier, faster, secure, not render things impossible because it does not know how to handle it because it wants to do too much.
For years (actually 20), I've been installing Linux on various machine using various distro to end up using exclusively debian because, I was able to tune the system as I want and not because other have decided I MUST do it in whatever way.
For machines I really manage, I have a separate /usr, no initrd and self build kernel: 1) Why should I build modules when I always load them and hardware almost never changes. Its slower to start, does not bring any benefit, 2) I can even add binary blob in the kernel nowadays, so I do not need an initrd at all and the packages needed to build them are not even installed
3) There is not always places to copy / in /usr4) My grub setup does not enable initrd, nor UUID for rot file system because without initrd you just can't, 5) I have machine with a byte of bad memory, and specific grub setup. I do not think you will ever be able to guess the correct grub config 6) I have machine that do network boots, and do not mount /usr the usual way,...
The debian installer should first loudly warn that having a separated / and /usr may break things in the future but not forbid it. With that in place, new debian installations that have no good reason for different filesystem for / and /usr will be installed the preferred new way. Old folks that have been doing this for years on hundred of machines will eventually learn new tricks. People that are using this setup for reasons will still be able to do so.
So please, do not make that kind of proposition that you will never be able to transition gracefully...
-- eric