rcraid-dkms

AMD RAIDXpert driver as DKMS package

Foreword:

Many AMD mainboards for the AM4 socket based on the following chipsets come with RAID support:

• X370
• X399
• X470
• X570

But this RAID mode, which needs to be set in the BIOS, requires a specific driver for each OS. There is a driver for Windows, but for Linux AMD provides either a binary blob or the sources. When following the instructions, you will need to recompile the driver and install the kernel module on each kernel update and/or upgrade. Since we are in the 21 century and we have software like DKMS, we don't need to do this manually, but let it happen automatically.

Goal

Therefore we try here to keep the code alive for many kernel versions as possible and deliver it within a PPA for Ubuntu as a DKMS package.

Installation

Debian/Ubuntu

• Build from source

• Switching to RAID mode:

  • Boot Linux in AHCI mode.
  • Append modprobe.blacklist=ahci to GRUB_CMDLINE_LINUX_DEFAULT in /etc/default/grub
  • Run sudo update-grub
  • Restart
  • Switch to RAID mode
  • Boot your Linux installation from a RAID disk

Arch/Manjaro

• Download and unpack zip or:

git clone --branch patch-1 https://github.com/switchboy/rcraid-dkms.git

• From inside the "arch" directory:

makepkg -si

• This will compile sources and install package for current running kernel. If you need to make package for different kernel then you can use KVERS option. After installing, edit /etc/mkinitcpio.conf and add

MODULES=(rcraid)

• Then rebuild your initrd, for example:

mkinitcpio -p

Important Workaround if AHCI Cannot Be Disabled

Some systems fail to properly disable the AHCI driver even when blacklisted or disabled in BIOS. In such cases, the RAID array will not be detected automatically on boot.

The workaround is to manually unbind the AHCI driver and reload the rcraid module after boot:

1. Create a script /usr/local/bin/fix-raid.sh:

#!/usr/bin/env bash
echo "Unbinding AHCI devices..."
for dev in /sys/bus/pci/drivers/ahci/*:*; do
  echo -n "$(basename "$dev")" > /sys/bus/pci/drivers/ahci/unbind
done
sleep 2
echo "Reloading rcraid..."
modprobe -r rcraid
modprobe rcraid
echo "RAID array should now be detected."

2. Make it executable:

sudo chmod +x /usr/local/bin/fix-raid.sh

3. Run this script manually after each reboot if the RAID array is missing:

sudo /usr/local/bin/fix-raid.sh

This manual step is currently the most reliable way to get the RAID working if disabling AHCI fails.

---

Note: If you just plan on switching to rcraid, my advice is: don't.
Support from AMD for Promontory RAID on Linux is pretty much non-existent.
You will be way better off sticking with mdadm, zfs or lvm.

If you REALLY want this to dual-boot Linux/Win, also don't. Setting up virtualization
with KVM with GPU Passthrough today is really simple, and you will not need to
boot Windows directly on your hardware ever again.

Sidenote: If you decide to use rcraid regardless you might want to also install RAIDXpert.
Web interface isn't working properly on Manjaro, but rcadm is more or less usable.

Sidenote 2: If you ever decide to switch from rcraid to something else, you may find it useful
to know that deleting arrays only removes metadata. Partitions are still there, and can be
recovered with gdisk, gpart etc. I found out that offset for partitions is 1069056 sectors (512B).
So if you have partition starting at usual 2048 it will be at 1071104 after array deletion.

Further info

• https://thopiekar.eu/other/amd-raidxpress/

Thanks go to..

• To AMD to hand out the driver as source code at least. (Some history: Just think about Intel Poulsbo..)
  • https://www.amd.com/en/support/chipsets/amd-socket-am4/x370 - section Linux
• To Martin Weber (@martinkarlweber) for sharing patches to make the driver work on Linux >= 4.15.x
  • https://github.com/martinkarlweber/rcraid-patches