We distinguish both hardware and software capacities. Software capacities may be such things as connection pools, thread pools, memory pools, single threaded software modules, mutex locks, database locks etc. A connection pool is scalable, it can hold many connections. E.g. a database lock is not scalable, since there can be only one.
Quantification of capacities, can be done by ops engineers or performance testers. Each time a feature is to be released, its impact on the available capacities can be assessed with help of the mBrace Tooling. It provides full insight in the changes needed to optimize the capacities. After having prepared the load model (which is well supported by the mBrace Performance Model), a capacity optimization scenario with the model takes only minutes. This activity is decoupled from the critical path of the software development process. After Stage 2 the risk of insufficient capacities is reduced to zero.
Apart from using this Capacity Optimization capability to secure performance it can be applied to other purposes like optimizing software license expenditure and predicting the cost of cloud computing