Software System Design : 3 Key Principles for Building Scalable Systems

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Steve Jobs once said, “Design is not just what it looks like and feels like. Design is how it works.”

A good design is essential for developing a physical product or a software system. To create a highly functional solution, developers need to apply software system design principles to meet both functional and non-functional business requirements. This enables them to manage the complexity of the designing process and reduce errors right from the initial stages.

While the functional requirements can vary depending on the purpose of a software product, the non-functional requirements do not vary. For instance, be it an e-commerce store or an online learning platform, customers want 24/7 availability to transact with the systems at any given time—a key consideration in software system design.

Let’s first understand what software system design really means—and then discuss its key principles.

What is Software System Design? 

In simple language, a software system design is the foundation of any robust software application. Essentially, it’s the “blueprint” that converts business requirements into software structures. Software system design is the process of defining the elements needed to fulfill the requirements. Here are the essential elements of any software system design:

• Architecture – The software architecture is the foundational framework (or model) that defines the system structure and behavior.
• Components – Any software system is composed of multiple components each of which performs a specific function or group of functions. For example, functions like securing or managing data or enabling communication between various components.
• Modules – This is another building block of the software system – and represents a combination of components. Like components, modules are used to handle a specific task.

Note: Software components and modules are reusable and enable a modular design. It allows development teams to work on individual functionalities independently – without disrupting the entire software system.

• User interfaces – This element represents how the software components & modules are displayed to the user. An intuitive or user-friendly interface is necessary for any software interaction. For instance, a graphical user interface (GUI) comprises command buttons, menus, icons, and other visual elements.

Now that we understand the basics of a software system design , let’s understand its design principles. 

What Are the Principles of a Software System Design? 

Software design principles are essentially the guidelines that enable developers to create a good software design. These design principles are independent of the functionalities of the software system – and apply to any application.

Here are 3 principles of software system design:

High availability

High availability is the design principle that ensures that every software system remains operational and accessible to its users at any time. Typically, availability must be around 99.99% (or higher). This translates to a downtime of 8.64 seconds per day.

With this level of availability, the system design is considered as a reliable system that can withstand failures or disruptions. High availability is essential in software systems such as healthcare or e-commerce systems to ensure that users have continuous access to critical functions.

As a system designer, how can you ensure high availability? Here are some common solutions:

• Avoid system redundancy by using additional components or servers, which can take over whenever the main component fails
• Implement load balancing that distributes incoming requests evenly across databases (or servers) – to prevent overloading of any single component.
• Implement an automatic failover mechanism that can detect any system failure and switch to backup systems without any human intervention.

High scalability

Scalability is another system design principle required to develop scalable systems that can grow according to user demands. Modern systems must be able to handle rising volumes of data, traffic, and workloads. Scalability has a direct impact on the user experience. For an optimum user experience, the response time in any system must range between 100 to 500 milliseconds.

Here are some design-related principles for achieving high scalability:

• Break down (or decompose) the software system into smaller manageable components, which enable easier scaling whenever needed.
• Design loosely-coupled components, which have minimum dependencies on each other. 
• Adopt a service-oriented architecture (SOA), which organizes every functionality into services that communicate with each other through a defined interface.
• Implement horizontal scaling (instead of vertical scaling), which adds more instances of existing components (or services) – thus improving their workload handling capacity.
• Implement a caching mechanism that stores frequently accessed data or computations, thus improving both performance and scalability.

High throughput

Throughput is simply the speed at which any software system can process requests. In other words, the number of processed requests in any given time interval. 

The throughput metric can differ based on the type of software system. For instance, in a database system, throughput is measured by the number of queries processed per second. In a payment system, throughput is measured by the number of transactions per second.

How can you ensure high throughput in any system? Here are some common solutions:

• Use load-balancing techniques to distribute the workload evenly among different components.
• Write software code that is optimized for high performance or throughput.
• Implement caching by storing frequently used data in cache memory, which reduces the time taken for data retrieval.

Additionally, you can improve throughput (or processing speed) by upgrading hardware components like memory, CPU, and storage. Besides, you can increase your network bandwidth to improve the speed of data transmission.

Conclusion 

In modern software systems, system designing has emerged as equally important as the software development process. This is because application users expect software systems to have high performance, fault tolerance, scalability, and reliability.

A good system design is the “backbone” that delivers performance and efficiency to application users. In this blog, we have looked at 3 fundamental design principles that you can apply to any software product. By implementing these design principles, you can develop software applications that meet user expectations and adapt to changing business requirements. All the best!

While concerns about software system design remain valid, they can be overcome when partnered with the right expertise, such as RBM Software.

Connect with us to see a new revolution in your software system design.  If you are interested in implementing them in your business, contact us today and book your free consultation with us!