Re: [gentoo-dev] rfc: using /libexec

[Rich Freeman]

On Wed, Sep 7, 2011 at 5:31 PM, Joshua Kinard <kumba@g.o> wrote:

> Never once have I had any issues
> with separate / and /usr, and none of them use an initramfs.


Ditto here, but that doesn't mean that problems don't exist.  Right now the
problems are likely to be subtle, perhaps arising only with certain
combinations of hardware/etc.  Maybe if you had a bluetooth keyboard or
something it might not work, or maybe if /usr were mounted on a bluetooth
hard drive or something (do they even make those?).

However, long-term it seems likely that the problems will continue to grow,
as more and more upstream packages move away from supporting a /usr that
isn't available at boot.

My general suggestion has been to hold the line where it is until we have
better support for mount /usr in initramfs, and it sounds like this is well
underway.


> As far as initramfs, is this something that would need to go into the
> kernel?


Well, the kernel comes with code for making an initramfs, but most likely it
would be implemented in a separate package.  The initramfs isn't part of the
kernel - it is loaded by grub at boot time and its address is passed to the
kernel.  So, the file needs to be on /boot.

I also netboot some of my systems, and they have limits on the total
> size of the kernel image (7.2MB on one, ~40MB on another, etc), hence the
> need to keep this small or find another way to do things.
>

I think that pxelinux supports initramfs - I know it supports initrd at
least and I don't think it makes any difference at the bootloader level.  In
fact, things like network booting are one of the drivers behind the Fedora
project to have dracut mount /usr.  Their plan is to just move everything
into /usr, allow it to be NFS-mounted, and then with one mountpoint
everything the system needs is available.  Eventually in Fedora /lib and
/bin will just be symlinks into /usr.  That will work fine as long as dracut
mounts /usr.

Are there possibilities about breaking off just a small piece of openrc and
> putting that into /run (or /boot)?  Enough of the core scripts so that it
> can find /usr and mount it before continuing?
>
>
Well, it certainly could be done, but it doesn't seem to be the direction
anybody else is going.  Instead the plan is to just create a very minimal
initramfs that gets the job done.  Using it would just be a matter of
installing the file and editing the boot line to load it.  Or, you can use
something like dracut or genkernel and get a more robust one.

Disclaimer - I'm not speaking for anybody but myself here...

Rich