Shulou(Shulou.com)05/31 Report--

How to carry out network-aware DRS parsing in vSphere 6.5, many novices are not very clear about this. In order to help you solve this problem, the following editor will explain it in detail. People with this need can come and learn. I hope you can get something.

VMware's distributed resource scheduling (Distributed Resource Scheduler,DRS) can dynamically allocate and balance computing capacity and aggregate hardware resources into a logical resource pool. It can continuously monitor the utilization of the resource pool, intelligently allocate resources, and allow users to define their own rules and schemes to determine how virtual machines share resources and the basis for judging the priority between them.

Traditionally, DRS takes into account the utilization of computing resources (CPU and memory) between hosts and virtual machines to balance the load between hosts and place virtual machines at power-on. Usually this works well, because in many cases, CPU and memory are the most important resources needed for good application performance. However, because this approach does not take into account the availability of the network, it sometimes leads to the placement or migration of virtual machines to hosts that are already saturated with the network. If the application happens to be network-sensitive, this may have some performance impact.

DRS is network aware in vSphere 6.5, so it takes into account the network utilization of hosts and the network usage needs of virtual machines during initial placement and load balancing. This makes DRS load balancing and initial placement of virtual machines more efficient.

working principle

During initial placement and load balancing, DRS first provides a list of the best hosts to run virtual machines based on computing resources, and then uses some heuristics to determine the final hosts based on virtual machines and host network utilization. This ensures that the virtual machine gets the network resources and computing resources it needs.

The goal of network-aware DRS in vSphere 6.5 is only to ensure that hosts have sufficient network resources available as well as computing resources required by virtual machines. Therefore, unlike regular DRS that balances CPU and memory load, network-aware DRS does not balance the network load in the cluster, which means that when the network load is unbalanced, it does not trigger vMotion.

Network-aware initial placement

DRS performs the initial placement in two steps:

It compiles a list of possible hosts and sorts them based on cluster constraints and the availability of computing resources.

Then, select the hosts with the best ranking and network resource availability from the list of hosts.

Network aware load balancing

During the load balancing operation, DRS

First generate a list of possible migration suggestions.

Then it is recommended to remove the network saturation of the target host.

From the remaining recommendations in the list, it is recommended that the one that has the maximum balance improvement in computing resources and contributes to the availability of network resources on the source host to prevent the source host network from becoming saturated.

Host network saturation threshold

As mentioned earlier, DRS avoids overloaded hosts during load balancing decisions only if the network utilization exceeds a certain threshold. Therefore, unless the host network utilization is higher than 80%, DRS will consider the host to be a good candidate in terms of network resource availability.

If the network utilization of a host reaches or exceeds the saturation threshold, DRS treats it as network saturation. If all hosts in the cluster are network saturated, DRS does not migrate virtual machines with heavy network loads, because migrating virtual machines with heavy network loads to hosts that are already network saturated results in further degradation of virtual machine performance. When DRS cannot migrate virtual machines because of this behavior, it sometimes results in an unbalanced load on the cluster.

Monitor host network utilization

Starting with vSphere 6.5, you can monitor the network load distribution of hosts under the DRS monitoring tab in vSphere Web Client.

The network utilization of the host is the average of all physical network card (pNIC) usage on that host. For example, if the host has three pNIC, one of which has a utilization rate of 90% and the other two have a utilization rate of 0%, the network utilization of the host is considered to be 30%.

Is it helpful for you to read the above content? If you want to know more about the relevant knowledge or read more related articles, please follow the industry information channel, thank you for your support.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.