Capacity defines the ways in which the systems may be expected to scale-up by increasing hardware capacity based on the organisation's volume projections. For example, transactions per seconds, customers online, response time, and so on.

Capacity is delivering sufficient functionality required by the the end users. A request for a web service to supply 2,000 requests per second, when that server is only capable of 200 requests per second, will not succeed. This is because the server is unable to handle the requested capacity.

Architecture cannot provide sufficient capacity with a single node, and operations personnel need to deploy multiple nodes with a similar configuration to meet business capacity needs.