When I installed Ubuntu Natty back then, I enabled full disk encryption per this blog post (now no longer available). Basically, I created an LVM and encrypted it, the only part not encrypted is the boot partition.
As Natty is no longer supported, I want to upgrade my OS to a more recent version of ubuntu, probaly Ubuntu 12.04. However, I'm afraid that once I upgrade my computer won't boot up and that I won't be able to fix it.
Does anyone know if it's safe to upgrade the OS with full disk encryption? What file should I save and have accessible in order to do post-hoc fixing should issues arise? (eg, /etc/crypttab?)
I've been trying to not upgrade because of fear that things will break, but as Natty is no longer supported, the packages that I need are forcing me to upgrade. Please advise, thanks!