I want to add more storage. I have four 6tb drives, 1 is being used for parity and 3 for data. I was thinking of purchasing a 12tb drive but since its larger it would have to become my parity drive, correct? Which is good because later if I add or replace drives I can use up to 12tb drives....but at this point it just feels like a waste.

 

I guess what I'm wondering is if my understanding of what I just described correct.  I'm torn between getting a 12tb drive vs just just getting another 6tb drive (which the 6tb is cheaper).

 

 

At some point you will want a larger data drive, then it will be necessary to have the corresponding parity drive. When to make that transition is up to you. Drive prices trend downward, so the longer you wait, the cheaper it will be (theoretically). However, each occupied slot has a cost, so buying smaller drives when larger are available at a lower cost per TB seldom (never?) makes sense.

 

I don't buy drives until I need the space, which I personally define as having less free space on the array than my single largest data drive.  Your budget and priorities may differ.