We have seen that the guided partitioning on Ubuntu Server 12.04 makes life plain and simple for us, but if we want to walk from that well trodden path then we will need to delve a little more into the partitioning options. Using a manual partitioning plan will allow us to mount directories separate to / as required bit, moreover, will allow us to choose software RAID. This we may choose if we have 2 or more disks and do not have a hardware raid controller to use. The video will step us though the process of crating software RAID for the root file-system and swap, we can use the complete disks and do not need a separate /boot structure when GRUB 2 is used which is the default in Ubuntu 12.04.
Once installed we will look at dpkg-reconfigure mdadm so we can review how to make the root file-system bootable with a device failure; we have to do this also in the GRUB 2 config files /etc/default/grub . Once in place we can configure a simulated disk failure to see that we can still boot.