# Cant boot with kernel-3.0.1 and RAID [Solved]

## cst

So I have been happily using this settings since 2.6.31 with no problem and now after I try to boot with 3.0 I get the "no block devices found" error when kernel is activating device manager.

This is my grub.conf entry:

```
title=gentoo

root (hd0,0)

kernel /boot/jadro root=/dev/ram0 init=linuxrc ramdisk=8192 real_root=/dev/dm-3 dodmraid udev vga=791 usbhid.mousepoll=1

initrd /boot/initramfs-genkernel-x86_64-2.6.31-gentoo-r6
```

I also noticed an option in 3.0 config:

Autodetect RAID arrays during kernel boot which is currently set to y

Does this mean I dont need to use initrd anymore?

This is a RAID set up on motherboard level

How do I configure 3.0 to work properly with my RAID?

----------

## frostschutz

Raid Autodetect is old and deprecated, and it only works with 0.90 Metadata RAIDs, and also only if it's on MS-DOS Partitions with fd Raid Autodetect partition type. All other RAIDs, e.g. 1.2 metadata and/or GPT partition table, require Initramfs/Initrd to work. Which is the preferred solution as its much more flexible and also more reliable as the Initramfs could know the exact UUID of the RAID in question and also do early error handling for unclean RAIDs. That's the theory anyways.

 *Quote:*   

> This is a RAID set up on motherboard level

 

Okay that's something else entirely; the above only applies to Linux Software RAID (mdadm). Which is the superior RAID solution for Linux.

----------

## richard.scott

If your using the latest genkernel (v3.4.16) the old way of booting root on RAID won't work anymore    :Shocked: 

You need to do this to get it all to work:

```
# mdadm --detail --scan >> /etc/mdadm.conf

# genkernel --mdadm --mdadm-config=/etc/mdadm.conf ramdisk
```

to build your initramfs with mdadm support.

oh, don't forget to add the domdadm option to your kernel boot args as follows:

```
title=Gentoo (2.6.39-hardened-r7)

root (hd0,0)

kernel /kernel-genkernel-x86_64-2.6.39-hardened-r7 root=/dev/ram0 init=/linuxrc real_root=/dev/md2 vga=792 domdadm

initrd /initramfs-genkernel-x86_64-2.6.39-hardened-r7
```

Hope this helps someone.

Rich

----------

## cst

Isnt mdadm used only for software RAID? I never had to use mdadm before.

----------

## Mad Merlin

FWIW, your motherboard RAID is also software RAID (more commonly known as fake RAID), just a different (and generally worse) kind than mdadm driven software RAID.

----------

## cst

 *Mad Merlin wrote:*   

> FWIW, your motherboard RAID is also software RAID (more commonly known as fake RAID), just a different (and generally worse) kind than mdadm driven software RAID.

 

Yeah I know that, but im on dualboot so mdadm is not an option.

SOLVED: I have built a new initrd with genkernel and the system boots fine now, so I guess the 3.0 is some kind of a bigger change, because I didnt have to build new initrd with each kernel update for 2 years.

----------

