Hello group, I have a TS-669L that I'm looking...

Hello group, I have a TS-669L that I'm looking to set up as file storage and multi-media player. I'm populating all six bays with WD Red drives. I will have the server shut off most of the time. My question is what's the best configuration (RAID, Storage Pools and Volumes), to maximize my drive's capacities, and have some sort of protection in the event of a drive failure. Like I said, I'm not using the TS-669L as a server, but as an "on demand" multi-media player/file storage, which will be off most of the time.