Scalability is the term which connotes the capability of the system, model, or functions to cope with the evolving demands. It defines how well a hardware or software can adapt to the changing needs. For example, a network system started with few nodes but can be swiftly expanded to hundreds of nodes is said to be a scalable network. It is one of the major features that businesses count on these days to ensure hassle-free performance of their expanding businesses.
In economics, scalability is defined as the potential of businesses to cope with the growing economy within the organization. Any system whose efficiency and performance gets improved after adding hardware resources is said to be a scalable system. If in case, the design or system fails with the increasing demands, it is not a scalable system.
Scalability can be measured in multitude of dimensions, such as:
Functional scalability is an ability to accelerate the system by incorporating new functionality with fewer efforts.
Administrative Scalability is the ability to make use of single distributed system by large number of users and organizations.
Load Scalability is the ability of the distributed system to scale up/down the resource pool in order to accommodate workload. Herein, a component can be added, deleted, or modified as per the requirements.
Including this, there are several other dimensions as well wherein scalability can be measured, like generation or geographically.