How to increase available VM bandwidth

The tide of regionalization, especially now, is becoming more and more obvious. Server virtualization is not a new term. It emerged in the 1960s S. At that time, servers could only execute simple tasks. The number of servers increased rapidly, but the utilization rate was very low, leading to a waste of resources. Virtualization is to achieve a more cost-effective way to use servers. However, as the density of VMS increases, although the hardware cost of each VM gradually decreases, the network bandwidth becomes insufficient and the network is congested in the virtual world.
However, we can increase the available bandwidth provided to the VM by some means.
Add network port
The simplest way is to install a NIC on the server. Generally, when the server leaves the factory, only one or two integrated Nic interfaces are set on the motherboard. In addition, the expansion slot is used, we can increase the number of network ports through the expansion slot, but note that you should try to select a multi-port Nic, such as some PCI-X and PCI Express NIC with four independent ports.
Another method is to use an external Nic, such as a USB Nic. However, we do not recommend using USB NICs for servers. In particular, some virtualization platforms do not support exposing USB devices to VMS. Even so, they can be used in some cases.
No matter how network ports are allocated, it is best to reserve a port for management communication. You cannot allocate all network ports to the VM. A management channel must be set up between the VM and the host server, if your virtualization software allows you to expose a USB Nic to a VM, You can reserve a USB Nic for communication between the VM and the host server.
Although one network card can be shared among multiple VMS, the problem is that the bandwidth provided by a single network card is limited. All VMS bound to the network card use the bandwidth together. If possible, you should try to use a faster network card. For example, if you use a 10 GB Ethernet card, you can use several gigabit network cards.
Use virtual networks
If you cannot add a physical Nic, you can try to reduce the network bandwidth required by the VM.
One way to achieve this is to create a virtual network, which exists completely inside the host server. If you use Microsoft Hyper-V or VMware, at least one virtual network is created by default, each physical Nic used by the VM is connected to the vswitch. The vswitch is connected to the virtual Nic of each VM in sequence.
The Virtual Network provides the VM with a connection to the physical network, but it cannot access the physical network, so that we can use the role of the virtual network to uninstall some of the original communication to use the physical network, this reduces the demand for physical network bandwidth. For example, suppose you have a virtualized Web Server where the backend SQL Server database runs on another virtual machine and creates a virtual network between the Web Server and the database Server, in this way, the database query will not pass through the physical network port, and indirectly increase the available bandwidth of the VM.
Allocate Network Ports Based on VM requirements
Creating a virtual network can transfer a large amount of network communication to the virtual network. If this is not done, you can assign a network port according to the VM's requirements for the network. Of course, this can also be done when a virtual network is created.
Not every VM has the same requirements for network bandwidth. Therefore, it is unrealistic to allocate a network port to each VM. Therefore, the network requirements of each VM are analyzed, A reasonable combination of VMS with low bandwidth needs to share a network port makes it ideal to specify a dedicated port for the VM with high bandwidth requirements. For example, if you have an SQL Server, you should assign it an exclusive network port. On the contrary, for domain controllers and DHCP servers, they do not need much bandwidth, you can share a port.
In short, the available network bandwidth limits the VM density on the host server, but there are also many ways to increase the network bandwidth allocated to the VM, in the way to maximize the VM density, we will see more and more solutions.