Why is my RAID /dev/md1 showing up as /dev/md126? Is mdadm.conf being ignored?

I found the answer here, RAID starting at md127 instead of md0. In short, I chopped my /etc/mdadm/mdadm.conf definitions from:

ARRAY /dev/md1 metadata=1.2 name=ion:1 UUID=aa1f85b0:a2391657:cfd38029:772c560e
ARRAY /dev/md2 metadata=1.2 name=ion:2 UUID=528e5385:e61eaa4c:1db2dba7:44b556fb

to:

ARRAY /dev/md1 UUID=aa1f85b0:a2391657:cfd38029:772c560e
ARRAY /dev/md2 UUID=528e5385:e61eaa4c:1db2dba7:44b556fb

and ran:

sudo update-initramfs -u

I am far from an expert on this, but my understanding is this ...

The kernel assembled the arrays prior to the normal time to assemble the arrays occurs. When the kernel assembles the arrays, it does not use mdadm.conf. Since the partitions had already been assembled by the kernel, the normal array assembly which uses mdadm.conf was skipped.

Calling sudo update-initramfs -u tells the kernel take a look at the system again to figure out how to start up.

I am sure someone with better knowledge will correct me / elaborate on this.

Use the following line to update the initrd for each respective kernel that exists on your system:

sudo update-initramfs -k all -u

sudo update-initramfs -u

was all I needed to fix that. I did not edit anything in /etc/mdadm/mdadm.conf.

I had the same issue.

This solution solvd my problem: http://aubreykloppers.wordpress.com/2012/07/06/mdadm-devmd127/