With / on LVM, you're definately unable to boot if LVM has problems.with / on ext2 you're definately unable to boot if ext2 has problems.
sorry , but you can not compare the PB's it's not about the FS , but the device access
initrd ?This is a problem I've seen a number of times on HPUX. The OS disk isyou cannot extend / under HP-UX (they don't have initrd)
isn't it common for all *nix OSes that they have a small / with only the very essential libraries , binaries and conf'sbesides i don't see the difference with someone having / un one disk and /usr on another without LVM.