Capacity

According to ITIL, the capacity can be defined as "The maximum throughput that a configuration item or IT service can deliver. For some types of CIs, the capacity may be the size or the volume - for example, a disk drive".

The capacity management can be defined as "The process responsible for ensuring that IT service capabilities and IT infrastructure are able to meet agreed capacity and performance requirements in a timely and cost-effective manner. Capacity management considers all the resources needed to deliver an IT service and addresses the attendance of current and future capacity and performance needs of the business".