Description of problem:
A DDF RAID array is not automatically assembled during boot. This is not a problem on RHEL-8.7 with the same setup, where the array is assembled automatically.


In the following example, vdb and vdc are the array members, which were created by the following commands (commands from bug 2063791#c0):

# mdadm --create /dev/md/ddf --name=ddf --level container --raid-disks=2 --metadata=ddf /dev/vdb /dev/vdc
# mdadm --create /dev/md/vol0 --name=vol0 --level raid1 --raid-disks=2 /dev/md/ddf

After reboot:

[root@localhost ~]# lsblk 
NAME          MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
sr0            11:0    1 1024M  0 rom  
vda           252:0    0   20G  0 disk 
├─vda1        252:1    0    1G  0 part /boot
└─vda2        252:2    0   19G  0 part 
  ├─rhel-root 253:0    0   17G  0 lvm  /
  └─rhel-swap 253:1    0    2G  0 lvm  [SWAP]
vdb           252:16   0   10G  0 disk 
vdc           252:32   0   10G  0 disk 
[root@localhost ~]# blkid
/dev/mapper/rhel-swap: UUID="0decee34-0f1d-45b0-9d3f-8009b231bc55" TYPE="swap"
/dev/vdb: UUID="Linux-MDM-^M--M->M-o" TYPE="ddf_raid_member"
/dev/mapper/rhel-root: UUID="9a9fe13e-ce4e-4652-b721-19be708ef989" BLOCK_SIZE="512" TYPE="xfs"
/dev/vdc: UUID="Linux-MDM-^M--M->M-o" TYPE="ddf_raid_member"
/dev/vda2: UUID="7Tuwmx-f3J1-Kz3i-aHyN-hpPP-2ND9-8re8aY" TYPE="LVM2_member" PARTUUID="038a6f7d-02"
/dev/vda1: UUID="01a0d35f-9154-4225-abec-f166f84593d9" BLOCK_SIZE="512" TYPE="xfs" PARTUUID="038a6f7d-01"
[root@localhost ~]# cat /proc/mdstat 
Personalities : 
unused devices: <none>
[root@localhost ~]#


By comparing RHEL-8.7 and RHEL-9.1 systems, the following lines were found missing in /usr/lib/udev/rules.d/65-md-incremental.rules:


@@ -42,8 +42,6 @@
 ENV{nodmraid}=="?*", GOTO="md_imsm_inc_end"
 SUBSYSTEM=="block", ACTION=="add", ENV{ID_FS_TYPE}=="isw_raid_member", \
        RUN+="/sbin/mdadm -I $env{DEVNAME}"
-SUBSYSTEM=="block", ACTION=="add", ENV{ID_FS_TYPE}=="ddf_raid_member", \
-       RUN+="/sbin/mdadm -I $env{DEVNAME}"
 SUBSYSTEM=="block", ACTION=="remove", ENV{ID_PATH}=="?*", \
        ENV{ID_FS_TYPE}=="isw_raid_member", \
        RUN+="/sbin/mdadm -If $name --path $env{ID_PATH}"

After adding the two missing lines and restarting the system, the array was successfully assembled.


This problem also affects the system installation, where the array is not assembled and visible in the installer.


Version-Release number of selected component (if applicable):
RHEL-9.1
mdadm-4.2-4.el9

How reproducible:
Always

Steps to Reproduce:
1. See above

Actual results:
DDF RAID array not assembled automatically.

Expected results:
DDF RAID array assembled automatically.

Additional info:
The problem was found during verification of bug 2109030.