alt Hacker NewsBit rot was mentioned in the article, but then no solution was offered. I also haven't found a good solution, unfortunately. If you only have a couple of Terabytes you could create check sums of everything and then verify regularly, but I feel this approach doesn't scale very well if you have lots of data.
If you have lots of data, I would suggest using a filesystem designed for this, like ZFS or BTRFS. You would still have to spend in storage though, as ultimately protecting from bit rot requires redundancy.