How *NOT* to add a RAID disk to a linux computer.
Buy 4x3TB Seagate Barracuda drives and have them delivered.
Cut cable ties inside computer to see how many spare power connectors there are, slice through end of thumb wth scissors.
Discover drives don't come with SATA cables. Go to PC World the next morning to buy cables.
Discover PCWorld is actually Currys, and doesn't sell cables. Got to Maplins instead and buy cables and fixing screws.
Discover the 3.5" bays in the case don't have screw-holes, will need to use the 5.25" bays. Order 4x adaptor brackets.
Stack the disks on top of each other in the meantime and wedge in with packing foam.
Spend 2 hours connecting them up.
Discover the BIOS only recognises the first 0.8Tb of each drive and spend 4 hours working out how to upgrade the BIOS.
Fail to do this - BIOS files too big to fit on a 1.44Mb DOS bootable disk image.
Try to boot into Linux and discover BIOS upgrade installer is a DOS-only program.
Obtain source code and start compiling it to run in Linux, then discover Linux can see all 3TB of each drive.
Decide with a software RAID setup, the BIOS might be irrelevant.
Read zillions of contradictory How-To guides on the net for setting up linux software RAIDs.
Install mdadm. Run it. No sign of RAID.
Run fdisk. Discover fdisk only works on drives up to 2TB. Install parted.
Run parted. No sign of RAID. Decide to create partition tables on 4 separate drives.
Several hours googling to work out what format filesystem and partition table to use. Settle on 'ext4' and 'gpt'.
Run mdadm. Now have a 12TB RAID0 drive!!!
Read an article saying gpt not supported in Ubuntu. But it was written in 2006 so ignore it.
Put data on drive. Turn it off (so the packing foam doesn't burn down the building). Go home at 9.30pm on a Friday.
Reboot computer, discover RAID has disappeared. Try every diagnostic tool I can find but no sign of it.
Decide to recreate from scratch, even though this will wipe existing data.
Rerun mdadm, RAID reappears, with data intact! Reboot, RAID disappears.
Discover the mdadm 'name=' switch has to refer to '/dev/md0', not 'my_12tb_raid0', which wasn't mentioned on any of the How-To guides.
Rerun mdadm, reboot, RAID and data intact!
Discover the motherboard blocks access to the 5.25" bays so impossible to secure drives via brackets along both edges.
Secure drives to brackets and to case along one edge, screw brackets upside down to other edge of case to act as a ledge the drives rest on (3 hours).
Discover case fan not working, and drives are too hot to touch. Order new case fan.
Fan delivered, fit it, daisy chain it from the CPU fan power connector.
Job done :D