LVM and RAID1

[Mark]

Hi,

I read the intro to LVM and like the fact that I can add additional HDs without problems.
However, if I want to have everything running in a RAID1 configuration in case one of my hard disks decides to crash or break some
sectors, how do the two work together?
Do I first configure the RAID1 and put the LVMs on top of my md_ partitions?

How reliable is this, and how much performance do I loose?

Thanks,

MARK