I had a system with a single 40Gb PATA drive in it. It had two 160GB SATA drives in it too, but the SATA controller on the motherboard was not supported yet by Fedora Core 5. (It’s a VIA controller. VIA has drivers, but they aren’t stable yet)
I got a 2-port Adaptec SATA controller, hooked it up while moving the machine to a 3U case, and booted. Great, everything works.
I then added the two new volumes to my “VolGroup00”, and took the system down to the colo. Oh. shit. It won’t boot.
Why? because the initrd for the system didn’t have the Adaptec controller, so the system couldn’t see the extra physical volumes, so it couldn’t construct the logical volume group, so it couldn’t find the “root” disk.
I booted a Fedora Core 5 rescue CD. (I am, btw, looking for a 30-50Mb image that I can stick on /boot, and invoke from grub, which would be a serial-console happy rescue image. It should have sshd, and be able to dhcp an address ideally…. I was going to take apart some CD-based .iso, but I haven’t done hat yet)
I then fixed this by running mkinitrd properly, and the system found the right disks, and booted.
I thought: I don’t want all my disks in the same volume group if a screw up will prevent the system from booting.
I came across the command “pvremove”, which I proceeded to run on /dev/sda1 and /dev/sdb1. OOPS. System won’t boot again, because I actually destroyed the physical volumes (from LVM’s point of view), not removed them.
Another run through with the rescue CD. Need to figure out what to do. The command “lvm” is nice, because as a wrapper around all the commands, it also tells you quickly what are actual commands and not.
Now, I have: