Capacity management and planning is the process of determining the supply of compute and other IT resources needed by an organization to meet the dynamic demands for these resources. In the context of OpenStack, in this blog I describe Startup Capacity Management, when first building out the Cloud, and Operating Capacity Management, for ongoing updates to resources for meeting user demands on the cloud deployment.
Traditional IT capacity management has employed simple forecasting-based approaches for capacity planning of dedicated IT infrastructure running limited number of applications. However, with the advent of virtualization and Cloud-based services, simple approaches no longer suffice because of the dynamic nature of supply and demand. The supply side is dynamic – VMs can be placed on any host, and can be migrated between hosts. Performance of applications can be impacted by other applications sharing the same compute, storage or network infrastructure. The demand is also dynamic, with seasonal, weekly or monthly peaks and one off dynamic peaks. A fundamental step in making the datacenter efficient is to understand the supply and demand of the IT resources. The supply consists of the resources such as compute, storage and network and the demand arises from the applications and services consuming these resources to fulfill business needs.