Configuring your disks is really two parts

KVM host

I have two identical 16G SSD disks. The partition layout is

sda     16G
sda1   256M
sda2 15360M

sdb     16G
sdb1   256M
sdb2 15360M

Raid

md0 raid1 (sda1 sdb1)
md1 raid1 (sda2 sdb2)

Luks

md1 luks formatted

LVM

md1 is configured as lvm with a volumegroup called vg1

with two partitons

For my system I have two small SSD disks. They are 16G each. I will use those to install the KVM host on.