How to rebuild while preserving an LVM disk

[Cliff Avey]

I have an ancient (FC3) Fedora that I want to move to FC8. I figure it 
might be cleanest to just rebuild it rather that upgrading (if that's 
even possible, it's so old). I can blow everything away except one 
thing. Separate from my OS disk, I have to SATA drives built into a 
raid-0 with md, and then an lvm physical volume group built on that. I 
need to keep that, and I don't have enough room anywhere else to backup 
and restore it.

If I unplug the raid drives, and rebuild my system, how can I hook them 
back up? Is the configuration info describing the md array, and the lvm 
groups stored on my os drive, which I'm blowing away. How can I save 
and/or recreate it once I get the main system back up?

Also, I don't know if there have been major changes to md or lvm (or xfs 
for that matter, since the logical volume is formatted as xfs). Will I 
have any problems using drives set up with a relatively old version of 
this software.

Thanks for your advice.