Re: Fedora 17’s unified filesystem (/usr-move)

[Kay Sievers]

On Fri, Jan 27, 2012 at 14:10, Harald Hoyer <harald at redhat.com> wrote:
> Hello Testers and rawhide Users,
>
> Fedora 17 will locate the entire base operating system in /usr. The directories
> /bin, /sbin, /lib, /lib64 will only be symlinks:
>  /bin → /usr/bin
>  /sbin → /usr/sbin
>  /lib → /usr/lib
>  /lib64 → /usr/lib64
>
> Some reasoning behind this change is outlined here:
>  http://www.freedesktop.org/wiki/Software/systemd/TheCaseForTheUsrMerge
>
> The official Fedora 17 feature page is here:
>  https://fedoraproject.org/wiki/Features/UsrMove
>
> The needed changes to implement the unified filesystem are about to land in
> rawhide soon. New installations of rawhide/Fedora 17 will install the symlinks
> right away, and no special care needs to be taken
>
> Currently installed systems need some manual steps to convert the current system
> to match the layout of rawhide/Fedora 17. After that, the system can continue to
> be updated with YUM as usual.
>
> Some RPM packages in rawhide/Fedora 17 will carry a RPM dependency guard, which
> will make sure, they can only be installed when /bin, /sbin, /lib, /lib64 are
> symlinks and not directories like in Fedora 16 and older.
>
> The installed system’s base filesystem layout can not be safely altered, while
> the system itself is running on top of it. Dracut, the initramfs used to find
> and mount the root filesystem, can be instructed to convert the filesystem to
> match rawhide/Fedora 17’s expectations.

The former dracut ‘usrmove’ module has been renamed to ‘convertfs’. We
need to carry that option for quite some time through future releases
and want to name the module more generic for possible future needs in
that category.

This is the current version/build number:
 dracut-014-81.git20120202.fc17

Please build the custom dracut image now with:
 # dracut --force --add convertfs

On the kernel commandline dracut now looks for:
 rd.convertfs

In some cases, we still do not properly support multi-lib updates with
the current testing repo, without adding also the i386 repository to
the updated system; the f17-usrmove repo does not automatically copy
the 32bit libs in the 64bit repo. This issue will not happen when all
moves to rawhide.

These known bugs are fixed:
- rebuild of the dracut initramfs on the converted system had problems
with optimized i686 libs, which is fixed now

- the ntfs-3g was not part of the f17-usrmove repository and
installing the old package on the converted system broke its symlink
logic. The fixed package is built for f17-usrmove now.