[CentOS] UnRAID

has anyone heard of UnRaid at: http://lime-technology.com/

Seems interesting, runs from USB.

What I like is that you can add drives to your array without having to destroy it. And it lets you add any size drive that you want. You can mix, say 1tb and 2tb drives.

What other ways can I do this without UnRAID? Its limitation is that you cant do anything else and I would want to run other things like apache, mysql, etc.

-Jason