Scalability in Projects: Key Design Decisions for Unlimited Growth

Discover how scalability influences the success of a project and learn how to make the right design decisions from the outset to ensure efficient and sustainable growth.

In today’s world of ever-expanding use of technology, scalability has become a crucial aspect of project development. Scalability refers to the ability of a system to handle an increasing workload efficiently. However, scalability is not a product of chance. It is the outcome of design decisions made during the initial stages of a project.

Choice of technology

Choosing the right technology is one of the first design decisions to be made in a project. This choice can have a significant impact on scalability. Therefore, it is important to research and understand the capabilities and limitations of all the technologies intended to be used before selection for a project.

This includes:

• Understanding how the technology handles concurrency.
• Memory management.
• How it behaves under load.

Choosing a technology that is unable to handle the scalability demands of a project can result in performance problems and the need for future (and early) system redesign.

System architecture

System architecture is another design decision that can impact scalability. A well-designed architecture will enable the system to expand and adapt to increasing demands.

A system’s architecture must be flexible and adaptable:

• It must support the addition of new components and services without disrupting the operation of the existing system.
• It must be resilient and capable of withstanding component failure without causing a major service disruption.

Architectures such as microservices architecture and event-driven architecture can facilitate system scalability.

Advantages of microservices architecture

Microservices architecture has emerged as a solution that offers unprecedented scalability, enabling companies to quickly adapt to changing market demands and technological advances.

Microservices architecture is a software design approach that involves breaking down an application into a set of smaller services, each running independently and communicating with each other through well-defined interfaces, such as APIs. If you want, you can go back to the Mortgage Space and complete the process when you receive the SMS code.

One of the main advantages of microservices is the ability to scale horizontally. Instead of increasing the capacity of a single server (vertical scalability), microservices allow more instances of a service to be added across different servers. This not only enhances the manageability of workloads but also provides greater resilience to failures since a problem in one service does not affect the other services.

Microservices make it possible to optimise the use of resources by allocating more computing power to services that need it while running less demanding services with fewer resources. This dynamic resource allocation is not only cost-efficient but also ensures optimal application performance.

A key approach to designing an effective microservices architecture is Domain-Driven Design (DDD). Domain-Driven Design is a methodology that focuses on gaining a deep understanding of the business domain and creating models that accurately reflect that domain. Instead of focusing on technology or data structure, DDD places greater emphasis on business concepts and processes, enabling developers to create solutions that address actual business-specific problems and helping prevent bad practices such as excessive segmentation in microservices or, conversely, the creation of microservices with coupling between different domains.

Adopting DDD can help define clear boundaries between different business domains, ensure that each microservice has a clear purpose and is aligned with business objectives, and promote the creation of well-defined interfaces for communication between microservices.

Advantages of event-driven architecture

Event-driven architecture is a style of software architecture that promotes the production of, detection of, and reaction to events. It offers multiple benefits:

1. Scalability: One of the main advantages of an event architecture is its ability to scale. Given that events are independent of each other, they can be processed in parallel, which allows for a high degree of scalability.
2. Decoupling: Event-driven architecture promotes decoupling between event producers and event consumers. This means that a change in one service should not require a change in other services, thereby facilitating scalability and maintainability.
3. Resilience: Event architecture can increase the resilience of a system. If one service fails, the events that it was unable to process can be handled by another service, which improves system availability.

But remember: as events are processed asynchronously, there may be a delay before changes are reflected throughout the system. It is important to check that this aspect meets the system requirements.

Database

Choosing a database can also affect scalability. Some databases are excellent at handling large volumes of data and supporting hybridisation in the cloud, while others can struggle in this respect. Similarly, database design, such as the choice of indexes and data normalisation, can impact scalability.

A well-designed database can handle a large volume of users and transactions. It is worth considering the use of techniques such as partitioning or even sharding (dividing a database into smaller, more manageable parts) and replication (creating copies of the database to distribute the load). When it comes to replication, CQRS is one pattern that you should look at in your project.

CQRS (Command Query Responsibility Segregation)

CQRS is an architectural solution that separates read operations (queries that read the state of the system) from write operations (commands that change the state of the system), thereby optimising both processes. This pattern offers several advantages, including:

1. Independent scalability: It allows for independent scaling of read and write systems, which is especially useful in applications with an uneven load between reads and writes.
2. Performance optimisation: Separating queries from commands permits optimisation of databases, data indexing and models for each type of operation, thus improving overall performance. Different database management solutions can be used for queries and commands.
3. Enhanced security: CQRS facilitates the implementation of specific security measures for reads and writes.
4. Simplicity in queries: Queries become simpler and streamlined as they are not mixed with command logic and command database design.
5. Maintenance and evolution: The clear separation of responsibilities makes the code easier to maintain and evolve over time. It makes it possible to increase the functionality of queries without affecting the performance of commands.

Use of caches

A cache is a technology that temporarily stores data in a quickly accessible storage space.

Its purpose is to minimise data access times and reduce the load on systems.

Using caching in your solution helps to:

• Reduce latency: Latency is reduced significantly by storing frequently accessed data in the cache, as the data is retrieved much faster than when having to access data repositories. Furthermore, responding more promptly to user requests results in a better user experience.
• Decrease workload: Caching can decrease the load on servers by eliminating the need to repeatedly process the same requests, thus increasing system efficiency.

Monitoring and alerts

Last, but not least, it is crucial to have a monitoring and alerting system that permits quick detection and response to any problems that may arise as the number of users increases.

Typically, the technologies selected for our system architecture already feature an out-of-the-box monitoring solution or support integration with existing off-the-shelf tools that can assist with monitoring and alerting management. It is essential to have a continuous monitoring and alert configuration based on rules or machine learning.

By doing so, problems can be proactively detected before they affect users, resources can be optimised by understanding how they are being used or detecting unexpected consumption peaks, and anomalies that could later become problems that affect our users can be identified.

Conclusion

Scalability is an essential element in project design. Design decisions made at early stages can have a significant impact on scalability. For this reason, it is crucial to address scalability from the outset and make well-considered design decisions. At CaixaBank, CaixaBankTech is the driving force behind the CaixaBank group’s technological transformation, responsible for ensuring the scalability of its solutions and guaranteeing that they can handle the bank’s constant growth and adapt to future needs efficiently.