Install Software RAID to existing Proxmox PVE installation

This is my notes of commands I have executed in Proxmox hardware node to add Software RAID capability to any Proxmox PVE existing installation:

apt-get update 
apt-get upgrade

apt-get dist-upgrade

apt-get install mdadm

modprobe raid1

                        (do not need to add to /etc/modules)

cat /proc/mdstat

Prepare partitions to Linux Raid Auto-Detect:

fdisk -l

fdisk /dev/sdb

    type fd  (change partition type to linux auto raid)

Copy partition from one drive to another

sfdisk -d /dev/sdb | sfdisk --force /dev/sdc

Remove previous RAID data if any:

mdadm --zero-superblock /dev/sdb1

mdadm --zero-superblock /dev/sdc1

Create the array with missing disk

mdadm --create /dev/md0 --level=1 --raid-disks=2 missing /dev/sdb1

Create the array with both disk

mdadm --create /dev/md0 --level=1 --raid-disks=2 /dev/sdb1 /dev/sdc1

To Add Secondary Drive Later do
mdadm --manage /dev/md0 --add /dev/sdc1

-----------------------------------  (if using LVM use this section below) -------------------------------

umount /mnt/md0

cat /proc/mdstat

pvcreate /dev/md0

vgcreate vglocalmd0 /dev/md0

lvcreate -n localmd0 -l 90%FREE vglocalmd0

-or-

lvcreate -n localmd0 -l 100%FREE vglocalmd0   (allocate 100% - but backup using snapshot will fail)

mkfs.ext4 /dev/vglocalmd0/localmd0

blkid      (to get and copy the uuid)

nano /etc/fstab

UUID=<uuid> /mnt/md0 ext4 defaults,noatime,nodiratime,noacl,data=writeback,barrier=0,nobh,errors=remount-ro 0 2

rm -rf /mnt/md0/*

chmod 777 /mnt/md0

mount -a

df -h /mnt/md0      (just to check and make sure the mount is there and okay)

-----------------------------------  (if using NON-LVM (just ext4) use this section below) -------------------------------

Create the filesystem

mkfs.ext4 /dev/md0

Double check to make sure all okay:

cat /proc/mdstat

Create mount target

mkdir /mnt/md0

chmod -R 777 /mnt/md0

---------------------- end of (LVM / Ext4 configuration -----------------

Edit fstab

blkid

nano /etc/fstab

UUID=<UUID> /mnt/md0 ext4 defaults,noatime,nodiratime,noacl,data=writeback,barrier=0,nobh,errors=remount-ro 0 2

mount -a

reboot