LunchB0xK1ller

10 GbE card in the server and the main workstation with a direct attach copper cable with help with transfer performance.

Not always true as in this case, the backplane he is looking at is a direct pass-through one built to use iPASS from Supermicro. It will directly pass a disk through to the controller with no speed reduction or size restriction. Currently my Unraid server is housed in a CSE-836TQ 16 bay chassis and I have a CSE-826A 12 bay JBOD chassis to have more slots attached with a external pass through card. The 826 chassis has a BPN-826A backplane in it now and currently houses 10TB drives. It passes through full capacity and speed. The "A" backplanes have one sff-8087 for every 4 drives and that is plenty of bandwidth for 4 spinning drives per connector. a SAS2 backplane is nice because it has one connector for all the drives but it is not a requirement as long as you have enough PCIE slots for the HBA cards. In my chassis I have two 8 port internal cards for the 16 bay chassis and one 16 port external card for the add on "A" chassis. This is just my $ .02 and my personal experience YMMV.