I also see this /dev/md_d127 array after reboot. It usually consists of a 1 to 3 devices that belongs to the real raid array.
I usually run
mdadm --stop /dev/md_d127 mdadm --assemble --no-degraded /dev/md0 /dev/sda1 /dev/sdb1 /dev/sdc1 /dev/sde1 /dev/sdf1 /dev/sdg1 /dev/sdh1 /dev/sdi1
to get the real array one running. Annoying!
This md_d127 gets created even if /dev/mdadm/mdadm.conf is empty.
# cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md0 : active raid5 sdb1[0] sdc1[8] sde1[9] sdf1[5] sdg1[4] sdh1[3] sdi1[10] sda1[1] 13674582656 blocks super 1.2 level 5, 64k chunk, algorithm 2 [8/8] [UUUUUUUU] bitmap: 2/466 pages [8KB], 2048KB chunk
# mdadm -Es ARRAY /dev/md/Apophis level=raid5 metadata=1.2 num-devices=8 UUID=2a54ea57:ce057f40:128e12a9:354e7dea name=:Apophis
I also see this /dev/md_d127 array after reboot. It usually consists of a 1 to 3 devices that belongs to the real raid array.
I usually run
mdadm --stop /dev/md_d127
mdadm --assemble --no-degraded /dev/md0 /dev/sda1 /dev/sdb1 /dev/sdc1 /dev/sde1 /dev/sdf1 /dev/sdg1 /dev/sdh1 /dev/sdi1
to get the real array one running. Annoying!
This md_d127 gets created even if /dev/mdadm/ mdadm.conf is empty.
# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid5 sdb1[0] sdc1[8] sde1[9] sdf1[5] sdg1[4] sdh1[3] sdi1[10] sda1[1]
13674582656 blocks super 1.2 level 5, 64k chunk, algorithm 2 [8/8] [UUUUUUUU]
bitmap: 2/466 pages [8KB], 2048KB chunk
# mdadm -Es ce057f40: 128e12a9: 354e7dea name=:Apophis
ARRAY /dev/md/Apophis level=raid5 metadata=1.2 num-devices=8 UUID=2a54ea57: