External Hard Drive "breaking" software raid 10.10 Server

[Miller88]

Ubuntu does not see any hardware RAIDs on this server - Intel confirms that they do not support Debian distros with this onboard SATA controller.

Tried going with CentOS and OpenSUSE ... CentOS would install, but wouldn't boot. OpenSUSE would work but after multiple installs, Samba wouldn't start.

That left us with Ubuntu Server.

While Ubuntu Server can't see a hardware raid, it can see each of the hard drives individually. From there, I created a software RAID during Ubuntu setup and was able to install.

Initially had some issues with mdadm "losing" the hot-spare ... was able to fix that by adding sd[abc][12] to /etc/mdadm/mdadm.conf ...

It worked fine until I plugged a WD MyBook usb hard drive into the machine.

I lose the hot spare (configured on /dev/sdc) because it mounts the USB hard drive there.

What I need help with
I need to be able to make it mount the USB hard drive AFTER mdadm configures /dev/sdc as the 3rd Hitachi hard drive


What needs to be done to make this work?

Thanks!

[Rubberman]

The problem is likely due to using the device id (/dev/sdxn) for drives instead of UUID's or volume names/labels to identify them. When you plug in new drives, the device ID's can change, which is why you are having this problem.