Dell Emulex Family of Adapters - Manual (Page 641)

Emulex Drivers for Windows User Manual P010077-01A Rev. A
3. Configuration
NIC Driver Configuration
641
For Windows Server 2012 and Windows Server 2012 R2, all existing RDMA
connections between the particular client-server pair, on which the failure occurred, are
torn down and recreated. After a certain number of unsuccessful retries, SMB traffic
falls back to TCP/IP.
The following event warning message is placed in the Windows System Log under the
source "be2net" indicating the adapter is running out of resources: “The Adapter ran
out of resources while creating the requested number of SMB Direct connections. Please
reduce the connection count to a supported value.”
Setting RoCE Parameters
You can set the RoCE adapter parameters using OneCommand Manager, PowerShell
scripts, or by using the Network Interface Property page.
Note: See the OneCommand™ Manager Application User Manual for more information
on using the OneCommand Manager GUI application to configure RoCE, or see
the OneCommand™ Manager Command Line Interface for information on using
OneCommand Manager CLI to configure RoCE.
The following parameters can be modified from the Network Interface Property page.
The following parameters can be viewed via the Statistics Property Page.
QoS Concepts Related to RoCE
Priority Groups
It is advisable to split traffic into two or more priority groups; one priority group for
RoCE and other groups for non-RoCE traffic. Many of the cluster applications use TCP
and RoCE traffic simultaneously. Some of them use TCP for establishing connections
and share connection-specific information. As a result it is important to allocate enough
bandwidth (greater than 1%) to non-RoCE (NIC traffic) to avoid a slow connection
establishment rate and starvation of NIC traffic. Work conserving behavior ensures that
each priority group gets enough bandwidth. Based on this behavior, non-RoCE traffic
should be given sufficient bandwidth; ideally 30-70%.
Parameter Description
NetworkDirect This parameter enables an offloaded RDMA interface for SMB 3.0
network-attached storage traffic using Microsoft's SMB Direct protocol.
NetworkDirect MTU This parameter configures the maximum transmission unit (frame size) for RoCE
traffic.
Note: For optimal performance, Emulex recommends setting the MTU size to
4096.
Parameter Description
RoCE QP Allocated Indicates the number of established queue pairs for RoCE.
RoCE Transmit Throughput The transmit data rate of RoCE traffic.
RoCE Receive Throughput The receive data rate of RoCE traffic.