[SOLVED] Can't boot from dmraid after recent upgrade

madman_xxx · 2015-10-18 11:07:25

Hello,

my arch system worked till yesterday, but after upgrade it no longer does. The problem is that although the software RAID device is recognized (/dev/dm-0 and /dev/mapper/isw_(hash)_(name) are visible), the partitions nodes are not created and I'm dropped to an emergency shell.
The arch wiki (kind of) addresses this issue (https://wiki.archlinux.org/index.php/In … RAID_array), but after the upgrade my gparted (on a USB stick, separate installation) also stopped working (some problem with libstdc++6, not to be elaborated in this post).
How can this be fixed, or at least investigated further?

I am using Intel's fake RAID embedded on my MSI Z97 Gaaming 3 mainboard.
Unfortunately, I cannot paste any configs, because my filesystems are no longer accessible. As far as I remember, the mkinitcpio.conf included the dmraid hook.

Last edited by madman_xxx (2015-10-20 22:39:54)

madman_xxx · 2015-10-20 22:39:15

OK, this was hell, but I got around it.

For starters - the solution here is more of a workaround, because it does not address the actual problem. Mostly because I still don't fully understand what the problem is, I only have the general idea. Also, the discussion on Arch's FakeRAID wiki suggest using mdadm instead of dmraid, but in my case it doesn't work and also I dual-boot Windows.

The configuration: I have been using dmraid + mdadm on Intel's FakeRAID. Worked till recent update
The problem: RAID seems to be detected, but there are no partition nodes (missing /dev/mapper/isw_(hash)_(name)p(x) and /dev/dm-[1-9])
The solution: Use dmraid only and force the system to recheck the devices for partitions after assembling an array. For that we must inculde partprobe in initramfs and invoke it upon loading the dmraid hook

run Arch installation medium for recovery, review the Installation Guide
assemble the array, but it should work out of the box
make sure you have parted installed on your crippled system. Use arch-chroot to install it if you don't. We will need the partprobe binary from that package

modify /usr/lib/initcpio/install/dmraid. This will include partprobe in the initramfs

#!/bin/bash

build() {
    add_module 'dm-mod'
    add_module 'dm-mirror'

    add_binary 'dmraid'
    add_binary 'dmsetup'
    add_binary 'partprobe'
    add_file "/usr/lib/device-mapper/libdmraid-events-isw.so"
    add_file "/usr/lib/udev/rules.d/10-dm.rules"
    add_file "/usr/lib/udev/rules.d/13-dm-disk.rules"
    add_file "/usr/lib/udev/rules.d/95-dm-notify.rules"
    add_file "/usr/lib/initcpio/udev/11-dm-initramfs.rules" "/usr/lib/udev/rules.d/11-dm-initramfs.rules"

    add_runscript
}

help() {
    cat <<HELPEOF
This hook loads the necessary modules for a dmraid root device.
HELPEOF
}

modify /usr/lib/initcpio/hooks/dmraid. This will execute the included partprobe after assembling the array

#!/usr/bin/ash

run_hook() {
    modprobe -a -q dm-mod dm-mirror >/dev/null 2>&1
    msg ":: Activating dmraid arrays..."
    # prevent any event monitoring calls with -I
    if [ "$quiet" = "y" ]; then
        dmraid -ay -I -Z >/dev/null
    else
        dmraid -ay -I -Z
    fi
    partprobe
}

modify /etc/mkinitcpio.conf. Make sure there is the dmraid hook before filesystems and mdadm_udev should be removed if it's there
regenerate the initramfs with
```
mkinitcpio -p linux
```
and you're done. Make sure that /etc/fstab is UUID-mapped, otherwise the system may still not boot because of the node name change, especially when you were using mdadm.

andrea993 · 2021-06-07 17:16:37

Hi, this guide is very helpfull. Only one thing, I suggest you to copy also the file to /etc

 cp /usr/lib/initcpio/install/dmraid /etc/initcpio/install/

This is because updating dmraid the file on /usr will be replaced and mkinticpio looks at /etc first.

I can suggest you to add this workaround in the dmraid wiki,

Scimmia · 2021-06-07 17:18:48

So add it instead of bumping a thread that's more than 5 years old.

ewaller · 2021-06-07 17:24:32

Using this opportunity to close this old thread.

Arch Linux

#1 2015-10-18 11:07:25

[SOLVED] Can't boot from dmraid after recent upgrade

#2 2015-10-20 22:39:15

Re: [SOLVED] Can't boot from dmraid after recent upgrade

#3 2021-06-07 17:16:37

Re: [SOLVED] Can't boot from dmraid after recent upgrade

#4 2021-06-07 17:18:48

Re: [SOLVED] Can't boot from dmraid after recent upgrade

#5 2021-06-07 17:24:32

Re: [SOLVED] Can't boot from dmraid after recent upgrade

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