The main goal of resource control in OpenVZ is to provide Service Level Management or Quality of Service for virtual machines and containers. Correctly configured resource control settings prevent serious impacts resulting from the resource over-usage (accidental or malicious) of any virtual machine or container on the other virtual machines and containers. Using resource control parameters for resource management also allows you to enforce fairness of resource usage among virtual machines and containers and better service quality for preferred virtual machines and containers, if necessary. All these parameters can be set using command-line utilities.
