Distributed versus Decentralized systems
Last updated
Last updated
When examining distributed and decentralized systems, the distinctions are often framed within the context of networked computer systems. As illustrated in Figure 1.1, each node represents a computer system, and each edge signifies a communication link between two nodes. The usefulness of such distinctions is subject to debate, especially as discussions about the pros and cons of each organizational structure unfold. For instance, centralized organizations are frequently criticized for poor scalability, while distributed organizations are praised for their resilience against failures. However, these assertions are not universally applicable.
Two perspectives can be adopted when considering how networked computer systems interconnect. The integrative view posits that there is a need to link existing computer systems, typically arising when services on one system need to be accessible to users or applications that weren’t originally contemplated. This is often seen in scenarios where financial services are integrated with project management systems or in scientific research, where expensive resources are pooled into a grid computer.
Conversely, the expansive view suggests that an existing system requires augmentation through additional computers. This perspective aligns more closely with the principles of distributed systems, emphasizing the need to expand capabilities by situating resources near where they are needed or enhancing reliability. For example, a service may need to be available for remote users through web interfaces or mobile applications.
These two perspectives help differentiate between decentralized and distributed systems:
Decentralized Systems: In these systems, processes and resources are inherently spread across multiple computers due to the need for integration or administrative boundaries. Examples include federated learning systems in AI, where training occurs closer to the data to comply with policies that restrict data movement. Additionally, decentralized systems like blockchain arise in contexts where trust among parties is limited, necessitating a public, verifiable record of transactions spread across multiple participants.
Distributed Systems: These systems, on the other hand, involve processes and resources that are sufficiently spread across multiple computers, primarily focusing on the need for scalability and fault tolerance. An example is Google Mail, where a vast network of servers enables users to send and receive emails seamlessly, ensuring high availability and minimal risk of data loss. Another instance is Content Delivery Networks (CDNs) like Akamai, which utilize numerous geographically dispersed servers to deliver content quickly and efficiently, optimizing performance based on user location and demand.
Conclusion:
The distinction between distributed and decentralized systems, though nuanced, highlights the varying motivations behind the organization of networked computer systems. While decentralized systems often arise from the necessity to integrate disparate resources, distributed systems prioritize scalability and reliability, expanding as user demands grow. Understanding these differences is crucial for designing systems that effectively meet specific operational needs and challenges.
