Move Mail RAID

Move the Mail RAID drive from Endeavour back to Gourd

OK, this can be done relatively risk free, but the order of the steps are important.

1. Prep the receiving system, in this case Gourd.
   1. Stop KVM: "systemctl stop libvirtd"
   2. Make sure /kvm /mail /home exist, and are empty directories.
   3. Make sure mdadm works (i.e. is installed.)
   4. Make sure all systems mount from "npghome" and some sysadmin idiot didn't hardwire 10.0.0.100 or another ip. Check /etc/hosts and /etc/fstab
2. Take down Einstein and Roentgen. Since they both depend on /mail and /home. (Actually Roentgen is optional, Einstein is not.)
3. Unmount /home, /mail from Endeavour. You may need to kill all users who are accessing the drives (not literally! Their process!)
4. Move the physical drive from Endeavour to Gourd. Yup, on a running system. It's OK. You need to take the drive out of the caddy and mount it in a Gourd caddy.