Paul wrote:
But how do I mount it when booted up on CD when it's burried somewhere in the LVM on hda2?
Boot normally, stop everything that uses it, unmount it.
If it's something you can't unmount (/, /usr, /var and alike), boot into rescue mode from CD. When prompted, let Anaconda find your existing CentOS installation. It will than create all devices and mount all file systems under /mnt/sysimage. Simply unmount what you need to unmount. Note, if you want to unmount root (and only if you want to unmount root) which is /mnt/sysimage, you'll need to unmount all filesystems under it first. As well as some stuff not shown as mounted by df command (not sure about exact list, try unmounting /mnt/sysimage/proc, /mnt/sysimage/sys, /mnt/sysimage/dev).