What are the best ways to improve network performance in VMware ESXi?

1 Optimize your network settings

Optimizing network settings in VMware ESXi is a crucial step for improving performance. Adjusting the MTU (Maximum Transmission Unit) can reduce the number of packets and improve throughput, but it can also increase the risk of fragmentation and packet loss. The default MTU is 1500 bytes, but you can use the esxcli network ip interface set command to change it. RSS (Receive Side Scaling) is a feature that allows a network adapter to distribute processing across multiple CPU cores, improving scalability and performance. It is disabled by default, but you can enable it by using the esxcli system settings kernel set command. Jumbo Frames are also an option, allowing you to use a larger MTU than the standard 1500 bytes, up to 9000 bytes. This can reduce the number of packets and improve efficiency and throughput. However, jumbo frames require more resources and configuration on your network devices and VMs, and they can cause compatibility and performance issues if not implemented correctly.

2 Use the right network adapters

In order to optimize network performance in VMware ESXi, you need to select the right network adapter for your VMs and your physical server. The three types of network adapters that you can use are E1000, VMXNET3, and SR-IOV. The E1000 is a legacy adapter that emulates an Intel 82545EM Gigabit Ethernet controller, but it has high CPU overhead and low performance, so it is not recommended for production environments or high-bandwidth applications. The VMXNET3 is a virtual adapter optimized for VMware ESXi with low CPU overhead and advanced features such as RSS, jumbo frames, hardware offloading, and SR-IOV. It is recommended for most production environments and high-bandwidth applications, but it requires VMware Tools to be installed on the VMs. Lastly, SR-IOV allows a physical network adapter to present multiple virtual network adapters to the VMs, bypassing the hypervisor and the virtual switch. This can improve the performance and latency of your network traffic but requires more resources and configuration on your physical server, your network adapter, your virtual switch, and your VMs. Additionally, it can limit the portability and flexibility of your VMs.

3 Monitor your network traffic

Monitoring your network traffic in VMware ESXi is an important way to improve performance and identify any issues or bottlenecks that may affect applications. You can use the command-line tool esxtop to access real-time information about resource usage and performance, including network statistics. The vSphere Client is a graphical user interface that provides access to the Performance tab and Network view, with charts and graphs for network performance and utilization. Additionally, vSphere Network I/O Control allows you to prioritize and allocate network resources for different types of traffic, as well as enable network quality of service (QoS) and apply traffic shaping policies. By using these best ways to improve network performance in VMware ESXi, you can optimize your settings, use the right adapters, and monitor your traffic to enhance the performance and reliability of your applications and VMs.

4 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?