Ubuntu – Installing Ubuntu Server 14.04 on a pre-built RAID Array

OK :) So here's your goal:

4 x HDD (2 TB), RAID 1+0. Single 4TB partition.

Seeing that it's only reporting around 1.6TB, that much missing storage suggests a meta-data problem to me.

I would suggest tearing down the entire array and ensure the metadata is wiped by using dmraid -rE. Then, once those disks don't show up anymore, try making a simple RAID1 from the 2 2T disks, your container capacity should be closer to 1.8-1.9 then 1.6. Once that is verified, then create your stripe, which ought to just add the two together. If this doesn't work you might have a bug in either the firmware or the dmraid system itself.

dmraid is ummm... interesting, given the choice I would prefer not to use it. You're basically taking all the complexity of md-raid, without any increase in performance, and then mixing in a slew of different metadata formats from different vendors, and then sharing that metadata with multiple operating systems, trusting that the OS you shared it with doesn't ruin the metadata.

You might want to test actually replacing failed members after you get this configuration stable, a RAID is just a big single point of failure if you can't service it. Good luck.

In response to your dmraid -rE issue At this point you're only option is dd if=/dev/zero ... and wipe the disks out.

The problem was that the drives became 'locked' at some point. This explains:

• The Input/Output errors I was recieving for all commands.
• The inability to format the drives or see them with gparted.
• The inability to boot with the disks in. (would have been helpful if the terminal didn't output this as SMART status BAD)
• The fact that I would get I/O errors on multiple computers showing it wasn't the cables/bus.

Once unlocked with a simple hdparm command sudo hdparm --user-master u --security-unlock p /dev/sdb(c) and a reboot, my mdxxx device became visible in gparted. I was then able to just sudo mount it to a folder and see all my data! I have no idea what caused the drives to 'lock down'. I am also missing the e2label it seems. I have no idea what this is. Perhaps someone can provide a better answer which explains:

• how the drives may have become locked in the first place (unplugging the drives while system is up/running/live?)
• whether this is not an mdadm array? or if it is why the configuration file didn't seem to show this?