MD RAID Array Status not Properly Updated on Removal of Last Component Device SLE 12

SUSE Linux Enterprise Server 12 SP5

On SLE 12 SP5, md0 is running in a healthy status. 

# mdadm -D /dev/md0

             State : clean
...
    Number   Major   Minor   RaidDevice State
       0       8       32        0      active sync   /dev/sdc
       2       8       48        1      active sync   /dev/sdd

After all components of the array have failed, failure of the last MD RAID component is not reported correctly.  

# mdadm -D /dev/md0

             State : clean, degraded
...
    Number   Major   Minor   RaidDevice State
       -       0        0        0      removed
       2       8       48        1      active sync

The command report incorrect information:

• RAID status is "degraded"
• Disks status is "active sync"

instead of the expected information:

• RAID status is "FAILED"
• Disks status is "missing"

SLE 12 SP5 will always have this restriction. Consider upgrading the system to newer SLE Version e.g. SLE 15 SP6. 

Due to a known limitation in the kernel used by SLE 12 SP5, the system won't reflect the correct array status when the final component is removed. 

On SLE 15 SP6, failure of the last MD RAID component is reported correctly. 

Array healthy.

# mdadm -D /dev/md0 

             State : clean
...
    Number   Major   Minor   RaidDevice State
       0       8       48        0      active sync   /dev/sdd
       1       8       64        1      active sync   /dev/sde

Array failed.

# mdadm -D /dev/md0

             State : clean, FAILED
...
    Number   Major   Minor   RaidDevice State
       -       0        0        0      removed
       1       8       64        1      active sync   missing