bug#38086: RAID installation script with ‘mdadm’ no longer works

[Ludovic Courtès]

Hello,

Looks like our RAID installation method no longer works, as can be seen
at <https://ci.guix.gnu.org/build/1906208/details>:

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+ guix --version
guix (GNU Guix) c4de60ac3c6aa5b46519011af89988215c347e9e
Copyright (C) 2019 the Guix authors
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
+ export GUIX_BUILD_OPTIONS=--no-grafts
+ GUIX_BUILD_OPTIONS=--no-grafts
+ parted --script /dev/vdb mklabel gpt mkpart primary ext2 1M 3M mkpart primary 
ext2 3M 600M mkpart primary ext2 600M 1200M set 1 boot on set 1 bios_grub on
+ mdadm --create /dev/md0 --verbose --level=stripe --raid-devices=2 /dev/vdb2 
/dev/vdb3
mdadm: chunk size defaults to 512K
mdadm: Defaulting to version 1.2 metadata
[   13.890586] md/raid0:md0: cannot assemble multi-zone RAID0 with 
default_layout setting
[   13.894691] md/raid0: please set raid0.default_layout to 1 or 2
[   13.896000] md: pers->run() failed ...
mdadm: RUN_ARRAY failed: Unknown error 524
[   13.901603] md: md0 stopped.
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Anyone knows what it takes to “set raid0.default_layout to 1 or 2”?

We should then update (gnu tests install) and the manual accordingly.

Thanks,
Ludo’.