Merging / onto /usr

Registered by Steve Langasek on 2012-04-03

Fedora has decided that they are going to merge {/bin,/lib,/sbin} into /usr. https://fedoraproject.org/wiki/Features/UsrMove This means that upstream support for distinguishing between / and /usr for early boot services will atrophy more than it already has, and there will be extra work involved for Ubuntu to maintain this capability. Furthermore, if we can rely on /usr to be mounted when upstart starts, we can simplify a number of system jobs. Explore whether we should change initramfs-tools in Ubuntu as well for 12.10 to provide this guarantee.

Blueprint information

Status:
Not started
Approver:
Steve Langasek
Priority:
Medium
Drafter:
Dimitri John Ledkov
Direction:
Approved
Assignee:
Steve Langasek
Definition:
Approved
Series goal:
Accepted for raring
Implementation:
Not started
Milestone target:
None

Whiteboard

Release Notes:
Ubuntu now treats /usr as an essential part of the filesystem. If your /usr directory is on a separate filesystem, this will be mounted from the initramfs instead of during early boot. By default on new installation, the installer will create symlinks to point /bin, /sbin, /lib, /lib32, /lib64 to their respective locations under /usr. For further details see: https://wiki.ubuntu.com/FoundationsTeam/Specs/Quantal/UsrMerge

(?)

Work Items

Work items:
implement support in initramfs-tools for mounting /usr before pivoting: TODO
send an additional call for feedback to debian-devel, ubuntu-devel to find out if this is going to impact Xen users: TODO
scan archive for double binaries (eg stuff in /bin and /usr/bin): TODO
add lintian check to detect new conflicts: TODO
fix all packages with double binaries: TODO
announce the changes and make it clear that we do not have to carry a delta from Debian: TODO
installer should make /bin, /sbin, /lib, /lib32, /lib64 symlinks into /usr on new systems: TODO

Dependency tree

* Blueprints in grey have been implemented.