Do you need to do some maintenance to keep the data in the array intact?

I read of some btrfs scrub commands and md checks and such, but I am unsure how often to do them, and what they actually do.

Thanks for the info!

Could you elaborate on btrfs on top of md raid?

This one seems the most likely solution for me.

What are the advantages of this over mdadm raid and bcache?

Are there some advantages of btrfs over raid? I understand how raid works but btrfs for redundancy is foreign to me.