October 30, 2023
App Modernization
Scaling for Success: Choosing the Right Path - Horizontal or Vertical?
In this article, we will delve into the concepts of vertical and horizontal scaling in the cloud, specifically focusing on how Amazon Web Services (AWS) users can achieve both simultaneously.

In the world of cloud computing, scalability is a crucial factor for organizations looking to meet the demands of a fast-paced digital landscape. Cloud technology offers superior capabilities for workload scaling compared to traditional on-premises infrastructure. It provides both vertical and horizontal scalability options, allowing businesses to optimize their compute and storage resources based on demand. In this article, we will delve into the concepts of vertical and horizontal scaling in the cloud, specifically focusing on how Amazon Web Services (AWS) users can achieve both simultaneously. We will also explore the implementation of auto-scaling on AWS, which eliminates the need for manual management of compute capacity.

Understanding Vertical Scaling

Vertical scaling involves increasing the capacity of an existing machine by boosting its compute, memory, or I/O capabilities. To put it simply, it is like replacing an inexperienced call center worker who can handle 5 calls per hour with a more experienced hire who can handle 10 calls per hour. In this case, the capacity of the existing role (the call center worker) is increased to handle higher throughput.

In the on-premises environment, vertical scaling typically involves adding new hardware or replacing components in an existing server to enhance its performance. This process may require ordering new machines, configuring them correctly, and physically installing them, which can take days or even weeks. However, vertical scaling on the cloud is much simpler. AWS offers a wide selection of instance types (virtual servers) with varying capacities to cater to different use cases. Users can easily upgrade or downgrade their instance types within seconds, allowing for seamless vertical scalability.

Exploring Horizontal Scaling

On the other hand, horizontal scaling involves adding new servers to distribute the compute, memory, or I/O load, reducing the burden on existing servers. Going back to our call center analogy, this would mean hiring more call center employees rather than replacing the existing ones with more experienced individuals. By increasing the overall capacity, organizations can handle a higher volume of work.

In the on-premises environment, horizontal scaling poses its own challenges. It requires ordering new servers, expanding physical data center capacity, installing the hardware, and ensuring load balancing across all servers. This process is time-consuming and may lead to a delayed response to changes in demand. However, AWS simplifies horizontal scaling by allowing users to spin up new instances and seamlessly integrate them into existing architectures within minutes. With AWS, IT teams no longer have to deal with hardware constraints, physical space limitations, or maintenance issues.

Combining Vertical and Horizontal Scaling

The true power of cloud scaling lies in the ability to combine vertical and horizontal scaling techniques. This allows organizations to find the optimal balance between performance requirements and budgetary limitations. By leveraging both approaches, businesses can achieve increased scalability and performance while keeping costs in check.

AWS provides auto-scaling capabilities that enable organizations to automate the addition, removal, or replacement of server instances based on predefined policies. There are three main types of dynamic auto-scaling policies offered by AWS:

  1. Simple scaling: This policy allows for scaling up or down based on a single scaling adjustment.
  2. Step scaling: With this policy, scaling adjustments are made based on a collection of predefined scaling steps.
  3. Target tracking: Scaling adjustments are made based on a specific metric, such as average CPU utilization.

The choice of auto-scaling policy depends on the nature of the application and the desired scaling approach, whether vertical or horizontal. Many organizations opt for horizontal scaling to avoid the need to stop existing instances for replacement. By combining auto-scaling with AWS load balancers, engineering teams can distribute traffic evenly across multiple instances and automatically scale up or down based on key metrics. This level of flexibility and automation is difficult to achieve in an on-premises infrastructure but is easily attainable with AWS.

Achieving Scalability with AltoStack

At AltoStack, we specialize in helping organizations across various industries adopt AWS architecture that enables virtually unlimited scalability. Our expertise lies in designing solutions that allow businesses to scale seamlessly with demand. Whether you are actively managing AWS servers or leveraging serverless solutions, our team of cloud engineers and solutions architects, with over 100 AWS technical certifications combined, can guide you towards success.

We understand the importance of scalability and its impact on performance and cost optimization. By implementing automated vertical and horizontal scaling on AWS, you can improve your application's performance, reduce resource underutilization, and ensure customer satisfaction. Our proven track record and expertise in large-scale cloud transformation make us the ideal partner for your cloud journey.


In the ever-evolving landscape of cloud computing, scalability is a critical factor for businesses seeking to meet the demands of a dynamic market. Vertical and horizontal scaling offer organizations the flexibility to optimize their compute and storage resources based on fluctuations in demand. AWS simplifies the process of scaling by providing a wide range of instance types and automated scaling policies. By combining vertical and horizontal scaling techniques, businesses can strike a balance between performance requirements and cost optimization. AltoStack, with its expertise in AWS architecture and scalability, can help you navigate the complexities of cloud transformation and ensure your success in the digital realm.