There are at least two comments in the lvm2 ebuild which claim that /usr shouldn't be required to run lvm: # 2. There are no longer any linking deps in /usr. # For recent systems, there are no linkages against anything in /usr anyway. Nevertheless, that assumption appears to be wrong on my system: # ldd /sbin/lvm | grep /usr | cut -f -2 libudev.so.0 => /usr/lib64/libudev.so.0 One solution is removing those comments, based on the fact that gentoo requires /usr to be pre-mounted by initrd, as of the 2012-03-16-udev-181-unmasking news item. I guess those comments might come from bug #80403 from 2005, so that aim of not requiring /usr might be considered obsolete these days. A far better solution, in my opinion, would be fixing udev to install this libudev into / instead of /usr. That way, lvm would remain usable even if something broke the /usr premounting, and I'd be able to manually recover my system without the need for an external boot medium. As this just happened to me (details in bug #417521), I know what I'm talking about.
I removed the comments. libudev is not moving to / instead of /usr, see bug 410147. *** This bug has been marked as a duplicate of bug 410147 ***
