Stux
6
I would suggest it is time to add another 6 disk VDev to each of your servers. Or even switch to a pair of 8-way!
This means you would want to move the mother board into a bigger case.
Perhaps a 24 bay case.
You would want to add an LSI SAS HBA.
Here’s a link to the build report of my 24 bay system I built back in 2017 
(Still going strong)
