Logical Volume Manager and RAID

[hendrik@topoi.pooq.com]

I'm planning to set up an array of two hard disks as a software RAID in 
and AMD64 box.  TO have some flexibility, I'm also planning to use LVM.
How does RAID interact with LVM?  Do I place RAID on top of LVM or the 
other way around?

Or am I worrying unnecessarily: Is it possible to mix them arbitrariy 
in multiple layers  -- some LVM partitions on a RAID drive that's split 
as two LVM partitions on physical hard disks? ( I can't imagine 
why I'd want to do anything that convoluted, but if I knew it's that 
flexible I'll worry less about accidentally breaking something. :-)

Also -- are the file system and partition formats identical no matter 
whether I run this Debian-only box with an AMD64 kernel or an i386 
kernel?

-- hendrik