sudo vgcreate BestEver /dev/sda4 /dev/sdb1
sudo lvcreate -i2 -I4 -l 100%FREE -n lvroot BestEver
sudo mkfs.ext4 /dev/BestEver/lvroot
mount /dev/BestEver/lvroot /mnt

dd if=/dev/urandom of=testfileR bs=4k count=10000; sync;