Load Balance Algorithms

Gilberto Machado
3 min readJun 29, 2023

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In this article, we will explore the algorithms used in Load Balance to achieve its purpose.

This is the second article about Load Balance, and you can find the first article here. In the previous article we discussed the introduction to Load Balance and its importance.

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Introduction

To ensure efficient utilization of available resources and improve overall system performance, Load Balance considers some factors such as server capacity, active connections, server health, response times among others. These algorithms make decisions on how to best distribute the incoming requests.

Summary of Load Balance Algorithms:

Least Bandwidth

This algorithm directs incoming requests to the server currently utilizing the least amount of bandwidth. It helps prevent servers from being overwhelmed by network traffic. Although effective in managing network resources, it requires more monitoring and tracking of server bandwidth, adding more complexity.

For example, a file hosting service utilizes this algorithm to direct the users to the server with the lowest bandwidth usage. By doing so, it can alleviate overload traffic, allowing downloads to be faster and more reliable.

Round Robin

Round Robin is the most famous Load Balance algorithm. It distributes incoming requests sequentially to available servers in a circular order. It is a simple algorithm that is easy to understand and apply. However, it does not consider server health or response time in the distribution process.

Round Robin algorithm is commonly used in web applications with multiple backend servers. Round Robin ensures that the requests are distributed in a sequential and circular order. The first request goes to Server A, the second to Server B, the third to Server C and so on… This is very useful to prevent any single server from being overwhelmed and optimizes resource utilization.

IP Hash

This algorithm routes requests to servers based on the source and/or destination IP address. It ensures that requests from a specific user are consistently directed to the same server. While it can evenly distribute the request load with a well-designed hash function, it may not be effective when dealing with a small number of clients generating many calls. It also does not consider the server health, response time, or varying server capacities.

This approach is particularly useful in scenarios where maintaining session information is crucial, such as e-commerce platforms or applications with user-specific data.

Least Connections

This algorithm directs incoming requests to the server with the lowest number of active connections. Its notable advantage is adaptability to different servers capacities and workloads. This makes it more effective when handling requests that take a variable amount of time to process.

This algorithm is particularly useful in scenarios where response time and efficient resource utilization are crucial, allowing for optimal performance and improved user experience.

There are other algorithms, such as Random, which randomly directs the incoming requests to servers from the available pool. It is also possible to create Load Balance algorithms that consider factors such as the server health, location, and capacity. Additionally, variations of the afore mentioned algorithms, like Weighted Round Robin, which assigns different weights to the servers based on specific criteria.

Conclusion

Load Balance algorithms play a crucial role in ensuring efficient resource utilization and improving system performance. Each algorithm discussed in this article has its strengths and limitations.

Choosing the right algorithm depends on factors such as the specific use case, servers capacities, and the trade-offs between simplicity and more advanced considerations such as server health and response time. It is also worth noting that there are other algorithms available, such as Random, Custom Load, Least Response Time, just to name a few.

By understanding the characteristics of each algorithm, system administrators and architects can make informed decisions when implementing Load Balance solutions to achieve high availability, reliability, and optional utilization of resources.

If you read untill here I hope you like this article and if so let your clap, thank you!

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