DRS in vSphere 6.x and vSphere 7

By Victor Wu on 2020 年 08 月 08 日 • ( 1 Comment )

In this post, we will discuss the difference of DRS feature in vSphere 6.x and 7.0.

In vSphere 6.x, the DRS load-balancing algorithm runs every 5 minutes to study the host load balance in the cluster. When a cluster becomes imbalanced, vSphere DRS makes recommendations or migrates VMs based on the cluster’s capacity resources (CPU and Memory).

Identifies VM migrations that improve the host load balance
Uses vSphere vMotion to migrate VMs between the hosts in the cluster

In the Summary tab of a cluster provides an overview of the configuration and status of DRS. It also shows the current level of host load balance in the cluster.

In vSphere 7, the DRS load-balancing algorithm runs every minute. It focuses on the VM DRS score to make recommendations or to migrate VMs:

Uses VM metrics to calculate the VM DRS score and cluster DRS score
Identifies VM migrations that improve the VM DRS score
Uses vSphere vMotion to migrate VMs between the hosts in the cluster

The VM DRS score is a new metric that measures the execution efficiency of a virtual machine. VM DRS score considerations are VM resource requirements fulfillment and ESXi host resource capacity. DRS migrates VMs to the host that provides the highest score and ensures fair resource allocation to all VMs. The VM DRS scores are filed into one of five buckets. These buckets are 20 percent ranges. A score of 80-100% indicates little to no resource contention.

The Cluster DRS and VM DRS scores replace the balance deviation level in the cluster.

The Cluster DRS score is a new metric that averages the individual scores of VMs. DRS focuses on maximizing the VM execution efficiency rather than on the host load balance in the cluster.

A VM DRS score is computed from an individual VM’s CPU, memory, and network metrics. You can use these metrics to gauge the pros or cons of the virtual machines.