Install OS on RAID1 thanks to dual SATA board?

[markb1]

Got my RockPro64 today.
NOTE: Updated with step 7. Now it survives a reboot!

First experiment: RAID1 on SATA via BTRFS, with boot on SD card
Result: easy! Not hard once you know what you're doing!
Steps:

1. Image an SD card with Armbian and boot up
   
2. SSH in to it, login as root, and follow the prompts to create a user account
   
3. Re-login via the user account (no strictly necessary, but I like a little protection from messing up the system as root)
   
4. Partition the disks
   
   1. sudo fdisk /dev/sda
      
   2. create a partition table
      
   3. create a new partition to fill the disk
      
   4. repeat for /dev/sdb
      
5. sudo nand-sata-install
   
   1. Select the option "Boot from SD - system on SATA..."
      
   2. Choose the partition /dev/sda1
      
   3. Choose the filesystem btrfs
      
   4. Allow it to complete and then reboot the system
      
6. Now that your root directory is on /dev/sda1, time to make it a RAID1
   
   1. sudo btrfs device add /dev/sdb1 / #adds /dev/sdb1 to the filesystem
      
   2. sudo btrfs balance start -dconvert=raid1 -mconvert=raid1 / #converts the two-drive filesystem to RAID1
      
7. VERY IMPORTANT: DO THIS BEFORE REBOOTING!!!
   
   1. As root (or with sudo), create a file "/etc/initramfs-tools/scripts/local-top/btrfs" with the following contents:
      
      Code:

      #!/bin/sh

PREREQ=""
prereqs()
{
    echo "$PREREQ"
}

case $1 in
prereqs)
    prereqs
    exit 0
    ;;
esac

. /scripts/functions
# Begin real processing below this line

if [ ! -x /bin/btrfs ]; then
    log_warning_msg "/bin/btrfs does not exist or is not executable"
fi

/bin/btrfs device scan
   2. Make the file executable: "sudo chmod a+x /etc/initramfs-tools/scripts/local-top/btrfs"
      
   3. Rebuild the initramfs image: "sudo update-initramfs -u"
      
8. Reboot
   

And that's it!

If you want to use mdraid, it's going to be a little bit more work. You'll have to modify the nand-sata-install script, because it wants to format a partition. You'll have to remove that formatting part from the script and make it use a pre-formatted partition.