As you may know we use SMB as the storage protocol for several Hyper-V deployments using Scale-Out File Server and Storage Spaces which adds a lot value to your Hyper-V deployments. To boost performance Microsoft is using RDMA or SMB Direct to accelerate Storage network performance.
RDMA over Converged Ethernet (RoCE) allows direct memory access over an Ethernet network. RoCE is a link layer protocol, and hence, it allows communication between any two hosts in the same Ethernet broadcast domain. RoCE delivers superior performance compared to traditional network socket implementations because of lower latency, lower CPU utilization and higher utilization of network bandwidth. Windows Server 2012 and later versions use RDMA for accelerating and improving the performance of SMB file sharing traffic and Live Migration. If you need to know more about RDMA or SMB Direct checkout my blog post: Hyper-V over SMB: SMB Direct
With Cisco UCS Manager Release 2.2(4), Cisco finally supports RoCE for SMB Direct. It sends additional configuration information to the adapter while creating or modifying an Ethernet adapter policy.
Guidelines and Limitations for SMB Direct with RoCE
- SMB Direct with RoCE is supported only on Windows Server 2012 R2.
- SMB Direct with RoCE is supported only with Cisco UCS VIC 1340 and 1380 adapters.
- Cisco UCS Manager does not support more than 4 RoCE-enabled vNICs per adapter.
- Cisco UCS Manager does not support RoCE with NVGRE, VXLAN, NetFlow, VMQ, or usNIC.
- You can not use Windows Server NIC Teaming together with RMDA enabled adapters in Windows Server 2012 and Windows Server 2012 R2 or you will lose RDMA feature on these adapters.
- Maximum number of queue pairs per adapter is 8192.
- Maximum number of memory regions per adapter is 524288.
- If you do not disable RoCE before downgrading Cisco UCS Manager from Release 2.2(4), downgrade will fail.
Checkout my post about Hyper-V over SMB: