My understand in write-through is that the controller puts the data directly to/from memory where as write-back lets the CPU do it. Is that correct?
So neither method has anything to do with lost data due to a power outage? Only a cache backup (or a UPS) can save you there?
So if you spend the bucks on a cache battery backup don't you still have the possibility of losing data that is in the cache of the hard drives?