Continuing from the previous article on distributed systems, transparency in distributed systems refers to the ability to conceal the complexity of the system’s architecture and functionality from its users and applications. The goal is to provide a simpler and more unified perspective that is independent of the underlying intricacies, allowing users and developers to engage with and understand the system more simply. There are several types of transparency in distributed systems:
- Location Transparency: Users and applications are ignorant of the physical location of distributed system resources or services. A user does not need to know if a file or service is on the local workstation or another machine across the network.
- Awareness Transparency: Users engage with distributed resources in the same way they would with local resources, with no awareness of the distribution. In a distributed system, for example, accessing a file or database is done using normal read-and-write operations, just like on a local file system or database.
- Concurrency Transparency: Users and programs are insulated from the complexity of concurrent processing and are given the illusion of sequential execution. Multiple users or processes, for example, can access and alter shared resources at the same time without explicitly dealing with synchronization difficulties.
- Transparency in Replication: Users are unaware that numerous copies of data or services exist in the distributed system. A user using a replicated database, for example, is unaware that the data may reside in multiple locations for fault tolerance or load balancing.
- Failure Transparency: Users are protected from the effects of node or system failures. Despite failures, the system continues to run smoothly. In the case of a distributed database, if one node fails, the system continues to offer uninterrupted service by rerouting requests to other healthy nodes.
- Migration Transparency: Users are not aware of the migration of resources or processes inside the distributed system. For instance, a process may be relocated from one server to another for load balancing purposes, but users are unconcerned about the specifics of this migration.
- Transparency in Performance: Users are unconcerned about the distributed system’s performance characteristics. Users of a cloud-based application, for example, do not need to be aware of the underlying infrastructure’s performance or scalability features.
- Transparency in Scaling: Users are unaware that the system can scale horizontally by adding more resources or nodes. A web application, for example, can accommodate higher traffic without users realizing that additional servers have been dynamically added to support the demand.
Distributed systems strive to simplify the user and developer experience by providing various forms of transparency, allowing them to engage with the system as if it were a single, coherent unit. This complexity abstraction improves the usability, maintainability, and scalability of distributed systems.