mhddfs - One folder to rule them all

Recently, my data drive got full, so I had to add a drive in the computer.
Raid was either too expensive in terms of space, or in terms of reliability, additionally, it would have required me to purchase more than one hard drive…
I was considering switching data between different folders, to split the data across multiple disks, but this solution also lacks in flexibility on the long run.
This is when I remembered reading something in Linux Journal… Thanks Shawn!
As a one phrase summary, mhddfs allows you to span multiple file-systems as one big folder, regardless of the size.

Many more interesting details in this (conf) and this enlightening post (comparison with raid and greyhole)