Hi, thanks for choosing Dell. Would you be able to refer to from page7?   Dell EMC Networking - RDMA over Converged Ethernet (RoCE v2) - Cheat Sheet     [URL]  
Hello,   VMware announced that starting from ESXi 7.0 U2, vSAN nodes support RDMA, RoCE v2.   Have you ever tried to configure that on dell switch side ? 
OS10 - Enable RDMA - ESXi 7.0 U2