root on md raid 1 not out of the box for slackware current as of 2021-12-04

amaretzek · 12-05-2021, 01:16 PM

Hi!
When installing slackware current (as of 2021-dec-04) on a md raid level 1, the UUID doesn't make it to (/mnt)/etc/mdadm.conf and hence booting after installation fails.
I did this:
- boot with USB PEN drive
- setup md0 for root, metadate 0.90.
- start setup
- My workaround:
- - as soon as the mdadm package is on disk,
- - (in another terminal) mdadm -Es >> /mnt/etc/mdadm.conf
- finish setup and reboot
Hope this helps...

drumz · 12-09-2021, 11:03 AM

From README_RAID.TXT:

Code:

=== Finishing touches ===

After exiting the installer, we have just a few settings to tweak.

Start by switching into your actual installation directory:
 - chroot /mnt


Let's make sure LILO boots from the RAID arrays properly.  Using your
favorite editor (vim/nano/pico), edit /etc/lilo.conf:
 - add a new line (add it anywhere, but don't indent it):
     raid-extra-boot = mbr-only
 - You will need to change the following line:
     boot = <something>
   RAID 0 and RAID 5 users, change it to:
     boot = /dev/md2
   RAID 1 users, change it to:
     boot = /dev/md0
   
 - Save the file and exit your editor.
 - run "lilo".


Now's let's create a customized /etc/mdadm.conf for your system:
 - mdadm -Es > /etc/mdadm.conf
You should get something like this (note that this output is not consistent
with the instructions above):
  ARRAY /dev/md0 UUID=bb259b84:6bf27834:208cdb8d:9e23b04b
  ARRAY /dev/md1  metadata=1.2 UUID=ea798427:4ae79ea8:9e7e263d:5ae8f69e name=slackware:1
  ARRAY /dev/md2  metadata=1.2 UUID=4ca90e7a:99de6d09:f1f9ca9d:b2ea6e1b name=slackware:2

If this is done on a live running system, you will notice that the arrays
created with 1.2 metadata will show /dev/md/$name (e.g. /dev/md/1) instead
of /dev/md1 in /etc/mdadm.conf; this is perfectly acceptable, and actually
preferable, so you might want to go ahead and fix that now.

If you plan to run the generic kernel (which is probably necessary, but you 
are certainly welcome to try the huge kernel instead), then continue on to
the next section; otherwise, skip to the exit and reboot part.

amaretzek · 12-09-2021, 12:10 PM

This doesn't tell how to re-create initrd after setup before boot. But the initrd after setup has to contain mdadm.conf with the array specified, or boot will fail.

drumz · 12-10-2021, 02:54 PM

Quote:

Originally Posted by amaretzek

But the initrd after setup has to contain mdadm.conf with the array specified, or boot will fail.

Ah, I didn't realize that part. My raid array is just a data drive, not the root drive.

lazardo · 01-29-2022, 02:15 PM

Quote:

Originally Posted by amaretzek

This doesn't tell how to re-create initrd after setup before boot. But the initrd after setup has to contain mdadm.conf with the array specified, or boot will fail.

lilo man page: -x option

mkinitrd man page: -R option

amaretzek · 01-29-2022, 03:27 PM

Hi, thanks.
Meanwhile I figured a few things, some I have to re-check.
So, after "chroot /mnt" one can recreate intrd like this:
Minimum, something like this:
mkinitrd -c -k 5.15.17 -m ext4 -f ext4 -r /dev/md0 -R -o /boot/initrd.gz
More general:
cmd_mkinitrd=$(/usr/share/mkinitrd/mkinitrd_command_generator.sh -r)
# check if it is ok
echo $cmd_mkinitrd
# execute it
$cmd_mkinitrd
# for UEFI, copy to EFI partition
cp -ip /boot/initrd.gz /boot/efi/EFI/Slackware/

Now, I once had the BIOS picking up the EFI partition that didn't had the kernel and initrd.
I had to copy them to both EFI partitions (not in chroot!).

Concerning lilo, didn't test nowadays...