Good morning. Sorry for my English.
I have the exact same problem, but with a difference when I use the commands:
mdadm /dev/md0 --assemble /dev/sd[abc]
root@Server-Archivos:~# mdadm /dev/md127 --assemble /dev/sd[abc]
mdadm: /dev/sda is busy - skipping
mdadm: /dev/sdb is busy - skipping
mdadm: /dev/sdc is busy - skipping
I leave the same information to know if you can help me.
This is the syslog.