What are distributed systems?
Source: Dev.to
Introduction
“Distributed systems” is a commonly used concept today. The first time you encounter it, it may sound daunting, but the core idea is simple and can bring clarity when building such systems.
Historical Context
When software moved from a theoretical possibility to a practical reality, the architecture was straightforward: an application program ran on a single computer, and any required database ran on the same machine, communicating directly within that host.
As computers became more powerful, society increasingly relied on them—a phenomenon often called digital transformation.
Availability Challenges
With this transformation, software needed to:
- Be available when users want to use it.
- Be correct, returning consistent results.
Running everything on one computer introduced two major availability risks:
- Total crash – If the single machine fails, the entire system goes down, even if the failure is unrelated to the application or database.
- Service degradation – If the machine receives more load than it can handle, it may become slow rather than crash, still affecting availability.
Moving to Multiple Machines
To prevent a single point of failure, the solution is to distribute components across several machines. If one machine goes down, only a portion of the system is affected.
When the application resides on machine A and the database on machine B, they must communicate across a network. This communication between nodes is the essence of a distributed system.
Definition
In a nutshell, a distributed system is a set of machines (nodes) that communicate with each other through a network to serve a specific purpose.
Ongoing Challenges
While distributed systems enable today’s massive platforms, they introduce challenges such as:
- Node failures (e.g., machine A going down before receiving a response from machine B).
- Network partitions and latency.
These challenges remind us that there are no silver bullets; careful design and engineering are essential.