[CentOS] replace x86 with x64 system and reuse existing LVM

Mon Jan 10 00:23:18 UTC 2011
Nico Kadel-Garcia <nkadel at gmail.com>

On Sun, Jan 9, 2011 at 5:31 PM, Kai Schaetzl <maillists at conactive.com> wrote:
> I want to replace an existing 32bit with a 64bit installation (Centos 5).
> There's an existing LVM with lots of partitions. Most are used for Xen
> guests. The system itself uses only one of them plus a separate /boot
> partition that is not on LVM.
> What's the best course of action here? Should I do the reinstall with
> kickstart or better manually and reuse the existing filesystem? As I
> understand once LVM gets loaded it should find the volumes by itself, but
> will it be able to use the same naming scheme for instance? Or do I have
> to do some additional stuff, anyway?

Backup your existing configuration, especially /etc and /home, and
/var/ configurations, and re-install from scratch.

Swapping kernel and glibc dependencies live is very tricky, almost as
tricky as switching from i386 to sparc or ppc, and likely to break in
the niidst of the process, even with the backwards compatibility of
i386 components under x86_64 libraries. You'd otherwise have to boot
with an x85_64 kernel and glibc and operatte inside a chroot cage,
andn that's just bloody tricky to be sure you got it right to replace
components like glibc inside of.