Horizontal vs Vertical Server Scaling: The Best Choice for Your Business

Scalability is among the most critical aspects of running a server-based operation today. Modern marketing is unpredictable, and any product can go viral at any time. You must be ready to take advantage of such opportunities when they appear. Preparing your server infrastructure to handle such sudden growth should be your priority. 

Horizontal and vertical scaling are the two main ways to expand your resource pool and increase traffic capacity and performance. Today, we will explore server scaling through these two approaches. Let’s see what they offer!

What is Horizontal Scaling?

Horizontal scaling is also called scaling out. In this approach, you add more servers to the existing infrastructure to improve performance and capacity. Rather than buying newer components and upgrading one server’s hardware, you can buy entirely new servers to integrate into the network. 

• How It Works: Adds more machines (virtual or physical) to the network, all functioning as a united system.
• Common Examples: Expanding an e-commerce site’s infrastructure by adding servers during peak holiday sales.

• Strengths:

• Increases redundancy and lowers the risk of downtime.
• Enables load sharing, reducing the stress on any one server.

• Limitations:

• Requires load balancers to distribute traffic evenly.
• Managing multiple servers increases complexity, especially for non-distributed applications.
• Upfront costs of new machines and instances can fall out of budget. 

What is Vertical Scaling?

Vertical scaling is also called scaling up. When you scale vertically, you upgrade your existing machine to accommodate scaling resource needs. This includes upgrading the CPU for more cores, adding more RAM and storage, and even upgrading to a new generation of hardware if needed. This limits activities to a single machine and allows for easier management and optimization. 

• How It Works: Boosts the capacity of an existing server through hardware or virtual upgrades.
• Common Examples: Increasing memory and processing power on a database server to handle larger queries.

• Strengths:

• Easier to implement and manage since it involves only one system.
• Avoids the need for complex load balancing and data synchronization.

• Limitations:

• Limited by the physical hardware capacity of the server.
• It can introduce downtime during upgrades or maintenance.
• Lack of redundancy leaves the server as a single point of failure. 

Horizontal vs Vertical Scaling: Key Differences

What makes these two methods so different? On the surface, they seem relatively similar, with some minor changes. Practically speaking, these differences completely change how scalability functions. Let’s do a side-by-side comparison of these two:

1. Management

Managing horizontally scaled servers is different from vertically scaled ones. Notable distinctions include:

Horizontal Scaling

Horizontal scaling is difficult to manage. You need technical expertise to properly configure the system to work as one unit. Some of your major responsibilities include balancing server load, ensuring consistent security implementation, and guaranteeing data integrity. 

Vertical Scaling

Vertical scaling is easy to manage. You only need to configure and monitor a single machine. You can implement your desired configurations or modify the system without worrying about affecting other servers. 

2. Flexibility

Both solutions are excellent for scaling but offer varying levels of flexibility. Let’s explore what makes them so different:

Horizontal Scaling

Horizontal scaling is very flexible and lets you remove or add servers to the network based on need. For example, you can upgrade to a two-server configuration when traffic spikes. When traffic returns to normal, the second server can be removed from the network. This flexibility saves resources and reduces operational costs. 

Vertical Scaling

Vertical scaling is less flexible. You cannot add and remove resources as needed. To add resources, the server must be taken offline and physically upgraded. Similarly, you cannot downgrade to less power-consuming components when traffic is slow. This inflexibility makes vertical scaling a poor choice for businesses with unpredictable growth.

3. Cost

Cost is a key metric every entrepreneur aims to control when scaling. Here’s what you can expect from these two scaling techniques when it comes to expenses:

Horizontal Scaling

Horizontal scaling is more expensive because you must buy a new machine. You can reduce the cost by using refurbished hardware or buying discounted component bundles. Even so, every time you scale, you must have the up-front capital for new components, set-up, and integration. 

Vertical Scaling

Vertical scaling is less expensive but limited in how much it can scale. You only need to upgrade one or two components at a time to scale depending on resource needs. However, you cannot upgrade and scale past a certain point. 

Once you reach the best hardware available, you must upgrade the whole system for new generation technology. Upgrading from DDR4 RAM to DDR5 RAM, for example, requires many other components also to be upgraded. 

4. Downtime Risk

Horizontal and vertical scaling handle downtime risk very differently. Here’s how:

Horizontal Scaling

Horizontal scaling is amazing at handling downtime situations. Your best option to reduce downtime risk is to have multiple servers available. Since horizontal scaling involves adding extra servers, the infrastructure naturally becomes downtime-resistant.  

Vertical Scaling

Vertical scaling is not ideal if you want to prevent downtime. You only have a single server in a vertically scaled infrastructure. If that server fails, the system will go offline. You will also be forced to go offline to maintain or upgrade the server. Vertical scaling makes your server a single point of failure in downtime situations.  

Here is a summary table of the major differences between horizontal and vertical scaling:

When to Use Horizontal Scaling

Horizontal scaling is ideal for scenarios where traffic is unpredictable. It minimizes unpredictability and maximizes availability. Having multiple versions available also reduces the failure rate. This is crucial, as every minute of downtime can cost up to $9,000, according to Forbes¹. 

Horizontal scaling is commonly used in:

• E-commerce: To handle large numbers of simultaneous visitors during flash sales or seasonal events.
• Media Streaming: To distribute streaming load across multiple servers to ensure smooth performance.
• Microservices Architecture: To deploy independent system components across multiple servers, enabling flexibility and modular updates.

When to Use Vertical Scaling

Vertical scaling is for businesses that value optimized infrastructure with high-performance computing. Vertical scaling lowers management requirements and creates one centralized optimal hosting solution. The simplicity, efficiency, and cost-effective nature of vertical scaling make it appealing for tight-budget setups.

Vertical scaling is typically used for:

• Databases:  To provide additional memory and processing power to optimize querying in large relational databases.
• Legacy Applications: To run legacy applications and systems incompatible with distributed, modern architecture. 
• Analytics Systems: To run real-time analytics platforms that need high computing power for fast data processing.

Hybrid Server Scaling 

One often misunderstood aspect of the discussion is the compatibility between the two scalability solutions. The two solutions work very well together and can be implemented within the same infrastructure. What horizontal scalability lacks can be gained through vertical scaling and vice versa. 

This is the ideal way of implementing scalability today. Core components that cannot afford downtime can be scaled horizontally to accommodate traffic. Meanwhile, the primary server and any important database or operation-centric machine can be scaled vertically to remove performance issues. 

Challenges of Server Scaling and How to Overcome Them

Server scaling challenges are difficult to overcome, even in hybrid environments. You will face two major obstacles when trying to scale your server: 

• Managing Costs: A traffic surge does not necessarily convert into sales. Spending on scalability is a risk you must take, and be ready to shoulder the costs if it does not pay off. 
• Technical Expertise: Another major challenge is the technical expertise required to maintain scalable infrastructure. An IT technician typically costs $53,000/year², not to mention the difficulty of finding suitable talent after the Great Resignation³. 

Even with cloud solutions, these problems are hardly solved. In fact, statements by AWS suggest that the cloud is slowly losing popularity against dedicated servers⁴. 

Dedicated servers are a solid solution to the scalability problem. The trick is finding the right provider to maximize resource utilization and performance without extensive investment. 

Conclusion

Choosing between horizontal and vertical scaling depends on your business’s needs, infrastructure design, and growth expectations. For dynamic, high-traffic applications, horizontal scaling ensures redundancy and flexibility. Vertical scaling offers easy upgrades with minimal complexity if you want to scale core systems.

RedSwitches dedicated servers provide the perfect foundation for both strategies. It gives your business the flexibility, performance, and support to scale confidently. Contact us today and discover how our dedicated hosting solutions can power your growth effortlessly.

FAQs

1. What is horizontal scaling?
   Horizontal scaling involves adding more servers to a network to increase capacity and performance.
2. What is vertical scaling?
   Vertical scaling means upgrading an existing server’s hardware, such as adding more CPU or RAM, to handle more load.
3. When should businesses use horizontal scaling?
   Horizontal scaling is ideal for high-traffic applications, such as e-commerce or streaming platforms, where redundancy and flexibility are needed.
4. When is vertical scaling more appropriate?
   Vertical scaling suits applications like databases and legacy systems that benefit from more powerful single-server performance.
5. What are the main challenges of horizontal scaling?
   Horizontal scaling requires load balancing and managing multiple servers, which adds complexity and costs.
6. What are the limitations of vertical scaling?
   The physical limits of the hardware restrict vertical scaling and can introduce downtime during upgrades.
7. Can horizontal and vertical scaling be used together?
   Yes. A hybrid approach allows horizontal scaling for front-end traffic while using vertical scaling for databases and core systems.
8. How does horizontal scaling improve availability?
   With multiple servers, horizontal scaling ensures redundancy, reducing the risk of downtime and improving system resilience.
9. What are the cost implications of horizontal vs vertical scaling?
   Horizontal scaling requires a higher initial investment, while vertical scaling has lower upfront costs but limited scalability.
10. Why are dedicated servers ideal for scaling strategies?
    Dedicated servers like those from RedSwitches offer exclusive resources, scalability, and global locations. They are perfect for both horizontal and vertical scaling.

References

1: Forbes, The True Cost Of Downtime (And How To Avoid It), 2024

2: Glassdoor, 2024

3: Tech Target, 2023

4: Competition and Markets Authority (CMA), CLOUD SERVICES MARKET INVESTIGATION, 2024