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grub2 doesn't see mdraid by mduuid

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Hi, all!

My grub doesn't see mdraid (raid1) by mduuid. /boot/grub/grub.cfg:

set timeout=2

menuentry 'Funtoo, 4.14.97' {
        insmod gzio
        insmod mdraid1x
        insmod part_msdos
        insmod ext2
        set root='(mduuid/232d2317:1469bc36:e85fd34c:9136eb63,msdos1)'
        echo    'Loading kernel...'
        linux   /boot/vmlinuz-4.14.97-nat root=LABEL=rootfs ro domdadm
        echo    'Loading initial ramdisk...'
        initrd  /boot/initramfs-genkernel-x86_64-4.14.97-nat

If i replace "set root='(mduuid/232d2317:1469bc36:e85fd34c:9136eb63,msdos1)'" with "set root='(md/0,msdos1)'", then grub boot the system.

Grub was installed with the next command(sda and sdb are raid component devices):

grub-install --boot-directory=/boot/ --modules='part_msdos mdraid1x' /dev/sda

grub-install --boot-directory=/boot/ --modules='part_msdos mdraid1x' /dev/sdb

 mdraid UUID:

mdadm --detail /dev/md127 | grep UUID
              UUID : 232d2317:1469bc36:e85fd34c:9136eb63


How can i fix this?

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I have never tried to make grub see a RAID created with mdadm.  I always keep /boot somewhere off of the RAID.  So I don't know if either of these two suggestion will work.


1.)  Tell grub to use /dev/sda as it's root. Something like "set root=(hostdisk//dev/sda,msdos1)" in you grub.cfg would work for that.

2.)  Try installing grub on the RAID itself:  "grub-install --boot-directory=/boot/ --modules='part_msdos mdraid1x' /dev/md127"  Honestly though, I am not really sure that will work.


For easy recovery in the event of catastrophic error I have learned the hard way (HINT: Don't make typos when executing a wipefs command) that having /boot accessible without any bells and whistles is the best way to go.

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