SOLVED Raid-z2 Available Space

[Simpleone71]

I have upgraded my FreeNAS system from a 8 bay to 24 bay case and added an additional eight 4 TB hard drives to my original eight 4 TB hard drives. I wanted to create a 2nd vdev with the new drives in a Raid z2 configuration. When I created the 2nd vdev, since it has the same number and same size drives as my previous vdev, I assumed they would be the same as far as available space, but they aren't and I'm wondering why and if I didn't set up my first vdev correctly and it isn't using all the space. I have attached the screen shot, but in my first vdev (Raidz2) there is 16.6 TiB available. In my new vdev there is 29.0 TiB available. Again since the drives are the same quantity and size, why are the two different?

 

[Jailer]

What is the output of "zpool status" without quotes.

 

[gpsguy]

The two look the same to me.

If you compare the first lines for Raidz2 and Raidz2-b and add the used+available together, both yield ~29TiB.

Looking at the second line below each of them, used+available, both yield ~20TiB. This line represents the total usable storage after taking parity into account.

 

[Simpleone71]

Okay, that makes sense. I was taking it as available was total available and not the remainder after subtracting out usage.