Recently we have series of IT Camps on Virtualization and Private Cloud in Singapore. Check out Spiffy.sg article to find out more about the IT Camps.
One of the topics that generates quite a lot interests is the Hyper-V Network Optimization. We covered quite few network optimization technologies during the Camps. Here is a quick summary on these networking optimizations
- TCP Chimney offload
- VM Chimney
- VMQ
- Receive-Side Scaling (RSS)
TCP Chimney
TCP Chimney Offload is a networking technology that allows the work associated with moving data across a network to be offloaded from the host computer’s CPU to the physical network adapter. In Windows Server 2008, TCP Chimney Offload enables the Windows networking subsystem to offload the processing of a TCP/IP connection to a network adapter that includes special support for TCP/IP offload processing.
The offload capabilities must be enabled in the driver for the physical network adapter in the root partition.
VM Chimney
VM-Chimney (TCP Offload) allows the CPU workload associated with TCP/IP traffic to be offloaded to the physical NIC, reducing processor usage and increasing network performance. This has been available for physical host, now it is available for the guest operating systems.
VMQ
VMQ is a technology that allows the physical NIC to create unique virtual network queues for each virtual machine (VM) on the host, allowing network packets to be passed directly from the hypervisor to the VM. This reduces a lot of overhead normally associated with network traffic.
Note: If a NIC has support for both VMQ and VM-Chimney, VMQ will be used.
Receive-Side Scaling (RSS)
Receive-Side Scaling (RSS) resolves the single-processor bottleneck by allowing the receive side network load from a network adapter to be shared across multiple processors. RSS enables packet receive-processing to scale with the number of available processors. This allows the Windows Networking subsystem to take advantage of multi-core and many core processor architectures.
Jumbo Frames
Jumbo frames are Ethernet frames with more than 1500 bytes of payload. Conventionally, jumbo frames can carry up to 9000 bytes of payload, but variations exist. Many Gigabit Ethernet switches and Gigabit Ethernet network interface cards support jumbo frames.
Hyper-V Networking Best Practices
Use multiple network adapters on physical hosts
To ensure good networking performance, you should use separate physical adapters for the following different networks.
| Virtual machine network. The virtual machines should always be configured to use dedicated network interface to communicate to each other. Use NIC teaming for HA. |
| Host management network: The hosts should always be configured with dedicated network interfaces. These dedicated network interfaces are used for managing the parent partition, connecting to the domain, cluster management, and backups. NIC teaming for HA appliese here too. |
| Storage networking: The integrity and capacity of the network path to the storage infrastructure is critical to a successful Hyper-V deployment. Dedicated network interfaces should be used for storage connectivity, typically on a completely separate VLAN or switching infrastructure. Configure MPIO for HA. |
| Live migration: A dedicated network card should be provisioned for Live Migration of virtual machines within a Hyper-V cluster. This network is typically private to the Hyper-V hosts and is configured as the highest priority for Live Migration traffic. A dedicated network will ensure that Live Migrations perform reliably and quickly. |
Create virtual networks based on required communication
| If only communication between virtual machines is needed and not with the physical machine or the external network, only create a private network. |
| If only communication between virtual machines and the physical machine is needed, create an internal network. |
| If the virtual machines need to communicate with the entire network or the Internet, create an external network. |
Additional Resources
- Register for FREE online Training on Microsoft Technologies at https://www.microsoftvirtualacademy.com/
- Join IT Camps and Supercharge your career with Private Cloud
- Information about the TCP Chimney Offload, Receive Side Scaling, and Network Direct Memory Access features in Windows Server 2008
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