How do distributed systems enhance web scalability?

Distributed systems enhance web scalability by spreading the workload across multiple servers, reducing the load on individual machines.

In a distributed system, the workload is divided among several servers, each of which can operate independently. This means that if one server fails, the others can continue to function, ensuring that the system as a whole remains operational. This is known as fault tolerance, and it's a key feature of distributed systems that contributes to their scalability.

Scalability refers to the ability of a system to handle increased workload without a significant drop in performance. In the context of web services, this means being able to serve more users or handle more data as demand grows. Distributed systems enhance scalability by allowing for horizontal scaling, which involves adding more servers to the system as the workload increases. This is in contrast to vertical scaling, which involves upgrading a single server to a more powerful model. Horizontal scaling is generally more cost-effective and flexible, as it allows for incremental growth.

Another way in which distributed systems enhance scalability is through load balancing. This is the process of distributing network traffic evenly across multiple servers to ensure that no single server becomes a bottleneck. Load balancing can be achieved through various methods, such as round-robin scheduling, where each server takes turns to handle requests, or more sophisticated algorithms that take into account the current load on each server. By spreading the workload evenly, load balancing helps to maximise the utilisation of resources and improve the overall performance of the system.

Distributed systems also enhance scalability through data replication. This involves storing copies of data on multiple servers, which can help to improve the speed and reliability of data access. If a user requests data that is stored on a busy server, the system can retrieve the data from a less busy server that holds a copy. This not only speeds up data access but also provides a backup in case of server failure.

In summary, distributed systems enhance web scalability by spreading the workload across multiple servers, allowing for horizontal scaling, load balancing, and data replication. These features help to ensure that the system can handle increased workload efficiently and reliably, making distributed systems a key technology for scalable web services.