Im making the move to unRAID from WHS 2011 later this week and im trying to plan out my drive structure prior to making the switch. I currently have:

 

1 1TB WD Black

5 2TB WD Green

1 3TB WD Red (Im looking to add 1-3 more 3TB Red drives shortly after the migration)

 

My question is, which drive should i be using as a parity drive and which should i use as a cache drive?

 

1 3TB = Parity

1 1TB = Cache

Your biggest drive HAS to be the parity, so your WD Red. As for cache you can use whatever you like. It doesn't need to have a lot of space so an older smaller drive is fine. But out of the drive listed there I would use the WD Black. Whatever you use for a cache drive I would be using a 7200rpm drive, not a green drive.

 

Or what ^he said.