How much space per gig of ram?

[RichTJ99]

I am going to reread as I think I am getting more confused. What I do remember is that in a multiple Vdev setup, if you lose one of the Vdevs you lose the whole pool (right)?

 

[depasseg]

Yes

 

[RichTJ99]

So it the triple mirror with 2 vdevs better than 2 mirrors with 3 vdevs?

 

[depasseg]

Yes - from a protection perspective as you can lose 2 of 3 drives in each mirror.
No - from a performance (speed and capacity) perspective, as vdev IOPS add together - more vdevs, better performance (generally speaking). Also, there is less usable space.