md127 issue, it should be /dev/md3 per mdadm.conf
Any time something is mounted as md127 it almost always means there is no entry for this mdadm array in the mdadm.conf in initramfs (which is separate from your actual /etc/mdadm.conf).
ARRAY /dev/md3 metadata=1.2 UUID=b6722845:381cc94e:7a2c5b5f:8e3b7c4f
The reason for this is something strange, most Linux OS's bizarrely always keep their own copy of /etc/mdadm.conf in the initram for the kernel, it will not automatically update or check the newest contents on your root partition.
This is why so many people have the problem and try different hacks and fixes that I have never seen work (eg. reassembling etc...).
Solution In Centos here is how you would fix the problem (assuming your /etc/mdadm.conf is correct/updated):