raid1-xfs.sh

export LANGUAGE="en_US.UTF-8"
export LC_ALL="en_US.UTF-8"
echo LANGUAGE=en_US.UTF-8 >> /etc/default/locale
echo LC_ALL=en_US.UTF-8 >> /etc/default/locale

apt update
apt install -y mdadm xfsprogs

lsblk -o NAME,SIZE,FSTYPE,TYPE,MOUNTPOINT

mdadm --create --verbose /dev/md0 --level=1 --raid-devices=2 /dev/vdb /dev/vdc

mkfs.xfs -f /dev/md0

mkdir -p /mnt/md0
mount /dev/md0 /mnt/md0

mdadm --detail --scan | tee -a /etc/mdadm/mdadm.conf
update-initramfs -u
echo '/dev/md0 /mnt/md0 xfs defaults,nofail,discard 0 0' | sudo tee -a /etc/fstab

ref

https://www.digitalocean.com/community/tutorials/how-to-create-raid-arrays-with-mdadm-on-ubuntu-16-04

change

mkfs.xfs -F /dev/md0

to

mkfs.xfs -f /dev/md0