After an hour with the server not appearing on the network, I started wondering what had happened. The console, it turns out, was displaying this message:
Creating root device Mounting root filesystem mount: error 6 mounting ext3 mount: error 2 mounting none Switching to new root switchroot: mount failed: 22 umount /initrd/dev failed: 2 Kernel panic - not syncing: Attempted to kill init!
Googling mount error 6 showed mostly complaints of disk and file system drivers not being compiled correctly, but further up the page (fortunately still on screen) I could see that the correct modules were being loaded. Pulling out my trusty rescue CD, I did a file system check. All fine. I tried recompiling the initrd file. All fine. I looked at the LVM information. All fine. Something niggled at the back of my head. I looked at the /boot/grub/grub.conf file. Then I discovered my error.
Concurrent to this reboot, I had renamed the logical volumes from the unhelpful (e.g. "LogVol00") to the sensible (e.g. "root_lv"). This can be done while the system is live (I discovered) so long as you also edit the /etc/fstab file to rename any device names. However, I hadn't renamed the devices in the Grub configuration - I usually make sure that the volumes are labelled and use root=LABEL=/root in the kernel parameters to set where the root volume is. So the kernel was looking for a non-existent block device and failing with the unhelpfully-named "mount error 6".
After a brief bit of enthusiastic head slapping, I fixed the Grub configuration, rebooted and all was well. Hopefully the next time someone encounters this error, they'll find this information useful.
All posts licensed under the CC-BY-NC license. Author Paul Wayper.