Slow storage spaces direct S2D setup
Solution 1:
You really need RDMA-capable 10 GbE for your backbone connectivity. 4x1GbE is simply not enough for Storage Spaces Direct. Get Mellanox ConnectX3 or similar cards, you can get used/refurb cheap from eBay.
P.S. S2D doesn't shine on a two-node config...
Solution 2:
I may try the 10GBe cards. Trying to pinpoint and prove that its networking that is holding me back. I just can't find evidence of it.
RDMA-capable 10GbE NICs is kinda a requirement for S2D. Also, just want to add that @BaronSamedi1958 is right about "S2D doesn't shine on a two-node config..." thereby I would recommend taking a look at SDS solutions that were designed for 2 nodes. First, that comes to my mind is HPE VSA they can create 2 node HA with cloud witness, either you can give a shot to StarWind VSAN they are using 2 nodes only, with no witness-node as the requirement.