S2D Reserve Capacity

Hi,

We are starting to implement S2D in our environment. Can anyone confirm how the reserve capacity thing works? Our nodes have 20 capacity disks so I want at least 2 disks worth in each node for reserve.

How do I do that? Is it literally just a case of not filling up the pool to the amount you want? I.e:

20X 600GB disks (+ 4X 800GB SSD for cache) = 24TB total physical storage
minus 4X 600GB for reserve = 21.6TB
divided by 2 (2 nodes, 2-way mirror) = 10.8TB usuable

So don't fill up the pool more than 10.8TB and you'll have 4 disks worth of reserve capacity?

Is that how it works?

Every time I read about setting reserve capacity I keep wanting to actually mark a physical disk as a reserve disk, like in the traditional hardware-RAID world.

Thanks