Storage QoS (Quality of Service) can help you manage risks around meeting your performance objectives. You use Storage QoS to limit the throughput to workloads and to monitor workload performance. You can reactively limit workloads to address performance problems and you can pro-actively limit workloads to prevent performance problems.
Storage QoS is supported on clusters that have up to eight nodes.
You assign a storage object to a policy group to control and monitor a workload. You can monitor workloads without controlling them.
The following illustration shows an example environment before and after using Storage QoS. On the left, workloads compete for cluster resources to transmit I/O. These workloads get "best effort" performance, which means you have less performance predictability (for example, a workload might get such good performance that it negatively impacts other workloads). On the right are the same workloads assigned to policy groups. The policy groups enforce a maximum throughput limit.
The following workflow shows how you use Storage QoS to control and monitor workloads: