Sur une debian 10, j'ai créé un raid sur 4 disques avec la commande suivante :
mdadm --create /dev/md0 --level=10 --raid-devices=4 /dev/sd[a-d]

J'ai semble-t-il perdu mon raid après un reboot.

# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
unused devices: <none>

# mdadm --detail --scan

ne retourne rien

# mdadm --detail /dev/md0
mdadm: cannot open /dev/md0: No such file or directory

# mdadm --assemble /dev/md0
mdadm: /dev/md0 not identified in config file.

# cat /etc/mdadm/mdadm.conf
# mdadm.conf
#
# !NB! Run update-initramfs -u after updating this file.
# !NB! This will ensure that initramfs has an uptodate copy.
#
# Please refer to mdadm.conf(5) for information about this file.
#
# by default (built-in), scan all partitions (/proc/partitions) and all
# containers for MD superblocks. alternatively, specify devices to scan, using
# wildcards if desired.
#DEVICE partitions containers
# automatically tag new arrays as belonging to the local system
HOMEHOST <system>
# instruct the monitoring daemon where to send mail alerts
MAILADDR root
# definitions of existing MD arrays
# This configuration was auto-generated on Thu, 30 Apr 2020 00:02:35 +0000 by mkconf

Qu'est ce que j'ai loupé ?

Par avance merci de votre aide.

Etienne