When it ran out of space, I picked up a third 2TB drive, stuck it in, and told the system "Add this drive to the volume." - which meant that I now had 4TB of space, with check-data spread across the three of them. And because technology is awesome it managed all of that while still working perfectly, and without me having to use a command line.
When we arrived back from Christmas this year, the box was unhappy. One of the drives wasn't working in when I turned it back on, so I ordered a new drive from Amazon. I picked up a 3TB one, because they were almost as cheap as a 2TB one, and I knew that I might want to expand again in the future**. I opened up the NAS, noticed that the non-functional drive was slightly loose, and pushed it back into place at the same time as adding the new drive. This then gave me four drives - and 6TB of storage***.
_Yesterday_ the system told me that one of the 2TB drives was dying. And because we're off on holiday tomorrow to see Julie's parents (and their six-month Alsatian puppy) I wanted to get this fixed before something died. And thanks to the wonders of Amazon and DPD I was able to order a new 3TB drive**** and have it delivered this morning - for a fiver extra. Which, frankly, for a Sunday is pretty amazing.
I poped open the NAS, took out the broken drive, slid in the new drive, closed it back up, and turned it back on again. Two minutes later it started beeping, and logging into the web interface it said "Your disk volume is broked. Want to repair it using that shiny new disk you just popped in?" All I had to do was click "Indeedly", and it's added the new disk to the volume, and is now busy moving things around to ensure that it's backing up the existing drives. At the end of that I should have about 7TB of space available*****. And I'm not using anywhere near that much!
Basically, computers are awesome, and it's never been easier to have oodles of storage that you don't need all of in your home.
*Network Attached Storage - a small computer with some hard drives in it that acts as storage that anything in the flat can talk to. Including the music player in the kitchen, the tablets, and the Playstation, so I can stream music and video from it to the TV. Better than an actual PC because it's tiny, low-power, and much easier to manage.
**Due to the way redundant disk arrays work, when you have a single drive bigger than the others the extra chunk isn't available, because there's nowhere to store the check data for it.
***Well, 5.36TB, because the "2TB" drives were actually 1.82TB. Because of computer maths.
****£85 for 3TB! Young Andy is boggled.
***** If you care about how it manages to do this, then see here. It's quite neat.
Original post on Dreamwidth - there are comments there.