Ensuring that applications and services remain constantly available and highly responsive is more critical than ever. A load balancer plays a key role in achieving this by distributing incoming traffic across multiple servers, optimizing performance and reliability.
To be precise, the load balancer market reached USD $7.09B in 2025 and is forecast to reach $13.79B by 2030, showing increased dependency on the technology.
Here we’ll explore what a load balancer is, the different types available, how it functions and the key advantages/disadvantages of using load balancing in your infrastructure. Let’s get started!
What is a Load Balancer?
A load balancer is a hardware or software device that sends network or application traffic across a group of servers. The key points in load balancing include improving an application’s performance, reliability and availability by distributing a load uniformly across a pool of servers.
This process helps prevent any single server from being overwhelmed with too many requests, which might cause a performance delay or downtime. Load balancers play a major role in the public cloud environment where high availability and scalability are essential.
Its applications range from web hosting, cloud services, enterprise applications and database management systems.
How a Load Balancer Works?
A load balancer acts as a reverse proxy, directing traffic efficiently across multiple servers. It assigns a virtual IP address (VIP) to the client requesting access to an application.
When the client connects to the VIP, the load balancer uses specific algorithms to determine which server instance should handle the request.
It then routes the connection and continues to manage and monitor the session.
You should think of a load balancer as a traffic controller, guiding requests to the correct destinations to avoid congestion and ensure smooth operations.
Its role is critical in maintaining the performance and security of an IT infrastructure, preventing bottlenecks and ensuring the seamless delivery of services.
Here is a simplified overview of how a load balancer works:
1. Receiving traffic
The load balancer receives incoming traffic from users or clients. It could be in the form of an HTTP request, database queries or other forms of network requests.
2. Load Balancing Algorithm Selection
The load balancer selects a specific methodology or algorithm, to decide how to distribute the arriving traffic. Examples of different algorithms that are typically considered are Round Robin, Least Connections and IP Hash.
3. Traffic Distribution
The load balancer uses an algorithm for routing requests to one of the backend servers.
4. Health Monitoring
The load balancers are used to monitor the backend servers’ health continuously. In case any of the servers fail to respond or malfunction, the load balancer stops routing traffic to those servers until they are up and running again.
5. Session Persistence (Sticky Sessions)
Some applications require the user session data to persist to a particular load balancer server. The load balancer can be configured for the persistence of sessions, so that users are consistently sent to the same server for the duration of their session.
6. Response Delivery
After the backend server has processed the request, the response is delivered to the load balancer, which routes it back to the client.
Also Read: How to Set Up Load Balancer with End-to-End Encryption?
What are the Types of Load Balancers?
There are several types of load balancers, each designed to handle different aspects of traffic management. Knowing them helps you identify the appropriate solution for your needs.
1. Hardware load balancers
Physical devices that are designed for traffic distribution. Most of the time, they are used in large-scale enterprise environments and data centers. These devices have dedicated hardware with specialized software running on it that can handle high volume of traffic and complex load-balancing algorithms.
| Pros | Cons |
|---|---|
| High performance due to dedicated hardware. | Expensive and requires physical space. |
| Often include advanced features and support. | Less flexible compared to a software-based solution. |
2. Software load balancers
Software load balancers are applications that can reside on regular servers. Because it is open source, it can easily be adapted to any specific requirements. These load balancers also support on-premises and cloud environments.
| Pros | Cons |
|---|---|
| Cheap and flexible. | It may experience performance issues under extremely high traffic compared to hardware-based solutions. |
| Easy deployment and configuration. | Overall performance depends directly on the server hardware underneath it. |
3. Cloud-based load balancers
The cloud service providers provide load balancers in the cloud. They are scalable and integrated with other cloud services. Examples are AWS Elastic Load Balancing and Google Cloud Load Balancing.
| Pros | Cons |
|---|---|
| Scalable and managed by the cloud provider. | Depending on the usage, they can get expensive. |
| Easy to integrate with other cloud services. | Less control over the underlying infrastructure. |
4. Global load balancers
Global load balancers balance the loads across different geographies. These are deployed for global application performance and route users to the closest or the best-performing server.
| Pros | Cons |
|---|---|
| Decreases latency for users in different parts of the world. | Complex in initial setup and management. |
| Improves the application performance running globally. | Sometimes, it takes further configuration to handle different regions effectively. |
What are Load Balancing Algorithms?
Load balancing algorithms are the rules a load balancer follows to decide which server should handle each client request. These algorithms fall into two categories: static and dynamic.
1. Static load balancing algorithms follow predefined rules regardless of the server’s current state.
Common examples include:
- Round-robin: The name server distributes traffic by cycling through the available servers one by one.
- Weighted round-robin: Servers are assigned weights based on their capacity, with higher-weighted servers receiving more traffic.
- IP hash: The load balancer uses a hash function on the client’s IP address to assign requests to specific servers.
2. Dynamic load balancing algorithms consider the server’s current state, such as load or response time, to distribute traffic.
Examples include:
- Least connection: Routes traffic to the server with the fewest active connections.
- Weighted least connection: Assigns traffic based on both server load and capacity.
- Least response time: Combines server response time and active connections to direct traffic to the fastest available server.
- Resource-based: Monitors server resources (CPU, memory, etc.) to distribute traffic to the server with the most available capacity.
What are the Benefits of a Load Balancer?
Load balancers have several advantages that can be helpful to an organization’s IT infrastructure.
1. Increased Availability
Since a load balancer distributes the traffic across multiple servers, in case one server crashes, others will take over. In other words, this redundancy minimizes the chances of downtime or application unavailability.
2. Enhanced Performance
The load balancer optimizes the application by balancing the load smoothly. It does not allow any server to act as a bottleneck and hence optimizes the response times and the user experience.
Recommended Read: Load Balancing in Cloud Computing – Types of Load Balancing and Load Balancers
3. Improved Scalability
Now, the inclusion of extra servers has made the job easy for the load balancer as it can scale the applications with ease. Scale additional servers online if the increased traffic warrants, then it will distribute the load accordingly.
4. Efficient Resource Utilization
Load balancers ensure effective utilization of all the servers by regulating the flow of traffic. This prevents a scenario where some of the servers are experiencing overload capacity while others have under or idle capacities.
5. Ease in Maintenance
In case maintenance or updates on any of the servers need to be carried out, a load balancer will shift the traffic from a particular server; this gives room for administrators to update without affecting any users. Once the administrators are done with the update, then the server is reintroduced to the rotation.
6. Enhanced Security
Some are designed with integrated security options, such as SSL termination and protection against DDoS attacks. These add an extra layer of protection for applications and services.
This makes more sense given nearly 40% of organizations suffered a major outage caused by human error over the past three years. Almost 85% of those incidents stemmed from failure to follow procedures or process flaws
What are the Disadvantages of a Load Balancer?
Though the load balancer has many advantages, its use also has disadvantages.
1. Increased Complexity
Load balancers can add complexity to your IT configuration. You have to make additional configurations to ensure this module spreads the traffic while completely monitoring all load balancer servers.
2. Cost
The cost could run accordingly depending on the type and size of the load balancer. Hardware load balancers can be expensive. Those provided as service offerings running from the cloud may involve more ongoing investments depending on the use cases. Of course, the cost has to be weighed against the advantages it provides.
3. Single Point of Failure
If not treated properly, it may result in a single point of failure. For increased availability, multiple load balancers with proper failover mechanisms must be introduced.
4. Performance Overhead
Though load balancers improve performance by design, they introduce some extra latency to the end-to-end transaction due to the processing overhead necessary for routing the traffic. It is generally minimal but may become a factor in highly performing environments.
5. Configuration and Management
Configuration and management of a load balancer require expertise. Incorrect configuration may result in inefficient traffic distribution, security vulnerabilities or performance issues. Continual management and monitoring are important for assuring optimum performance.
How to Choose a Load Balancer?
In our experience, you can choose a load balancer faster when you evaluate your application requirements in a fixed order, then map them to L4 or L7 features.
1. What protocols will you load balance? (HTTP/HTTPS vs TCP/UDP)
Ideally, you should choose an L7 load balancer for HTTP or HTTPS because it can understand requests and apply routing rules. Consider an L4 load balancer for TCP or UDP because it routes based on connection details with lower processing overhead.
2. Do you needhostor path-based routing?
You should use L7 routing when you serve multiple services on one domain or one IP address. This approach reduces extra public endpoints because the load balancer can route requests using the host header or URL path.
3. Do you need sticky sessions or can you go stateless?
We suggest you avoid stickiness when possible because it makes scaling and failover harder under node or instance replacement. If your app stores session state in memory, you may need stickiness until you move sessions to Redis or another shared store.
4. What traffic pattern do you expect? (steady vs spiky)
You should favor managed autoscaling features when traffic is spiky because manual capacity planning often lags behind real demand. Steady traffic can use simpler configurations. However, you should still plan headroom for deployments and failovers.
5. What compliance and security controls arerequired?
Make sure you confirm support for TLS termination, mTLS, WAF, detailed access logs and retention controls if your policies require them. These controls matter because the load balancer often becomes the security boundary for internet-facing services.
6. Do you need multi-region or global traffic management?
You should choose a solution that supports multi-region routing when latency targets require regional entry points. Additionally, you should confirm health-based failover behavior because cross-region outages need automated traffic shifting.
7. Which budget model fits your usage? (per-hour, per-GB, per-request)
Finally, you should estimate cost using your traffic shape because per-GB pricing can dominate for large responses or streaming workloads. Remember, per-request models can become expensive at high QPS, whereas per-hour pricing can waste budget at low utilization.
Leverage AceCloud’s Network Load Balancer
With modern IT infrastructure, load balancers have emerged as an inseparable component for ensuring application performance, reliability and scalability. Of course, while offering major advancements in availability and performance, load balancers also add significant complexity and cost.
In our opinion, a proper mix of considering such factors and getting the right load balancer for specific needs will be key to optimizing your IT infrastructure. Book a free consultation with an AceCloud expert today to learn how you can maximize business profitability via load balancers!
Frequently Asked Questions
A load balancer sits in front of your servers and distributes incoming requests across them. This improves availability because no single server gets overwhelmed.
You can choose hardware for dedicated performance, software for flexibility, cloud-based for managed scaling or global for routing users by geography. Your best option depends on traffic volume, control requirements and operational overhead.
Algorithms decide which server receives each request, either using fixed rules or real-time server state. You can start with round-robin, then move to least connections or least response time as traffic patterns evolve.
The load balancer presents a virtual IP to clients, then proxies each request to a selected backend server. It also monitors server health and stops routing traffic to unhealthy targets until they recover.
You should use session persistence only when your application stores session state on a specific server. However, stateless services usually work better because any server can handle any request safely.
A load balancer can add SSL termination and DDoS protections, which reduces direct exposure on backend servers. However, you should design for redundancy because a poorly designed load balancer can become a single point of failure.
