As an earlier post indicated, I'm running Fedora 14 Alpha. When you use non-released versions of Fedora, you might be said to be running Rawhide. I won't say that I wasn't warned that things would break occasionally, but this morning it BAD! When glibc broke, then the system became unbootable.
Lucky for me, I've got a USB key with Fedora 14 Live on it. Also fortunate, the Fedora Project already had an update that fixed the problem. All I had to do was boot up the Live USB, and do a few simple commands to fix it:
# vgchange -a y
# mount /dev/mapper/vg_host-lv_root /mnt
# yum -y --installroot /mnt update glibc
The first command searched my internal hard drive for LVM Volume Groups.
The second command activated the volume group (vg_host) that it found.
The third command mounted the logical volume (lv_root) for my root filesystem under /mnt.
The fourth command actually fixed the problem: it told yum to update the broken package, but to install the update under /mnt, where my real root filesystem is located.