Load Balance
Series about Load Balance:
Introduction to Load Balancing
This is the first article about load balance where I will dive into some of its concepts, give some examples of one of the most use concepts when comes up to improve the system performance and, also, a concept that is always asked in design system interviews.
Key Terminology and concepts:
Load Balance: A device or software that distributes network traffic across multiple servers based on predefined rules or algorithms.
Backend Servers: Servers that receive and process requests forwarded by the load balance. Could be called as server pool or server farm.
Load Balance Algorithm: Algorithm method used by load balance do determine how to distribute incoming traffic among the backend servers.
Health Checks: Test performed periodically by the load balancer to determine the availability and the performance of backend servers. Unhealth servers remove from server pool until recover from any issue.
Session persistence: The concept to ensure that any subsequent request from the same client is direct to the same backend server so it can maintain session state and help to provide a consistent user experience.
Load Balance
Load balance is a crucial component when designing a system, it helps distribute incoming requests and traffic evenly across servers. Normally a load balance sits between client and server receiving income requests and application traffic and distributing it across multiple backend servers using several types of algorithms.
Load balance reduces the load time on individual servers and prevents any server from becoming a single point of failure helping overall application availability and responsiveness.
To utilize it in whole way, using load balance in each layer of the application we can place the load balance putting it between user and web server and/or putting it between web servers and internal platform layer like application servers or cache servers or even putting it between internal platform layer and database.
Steps for Load Balance work:
- The load balance receives the incoming requests, like end user browser or another API call.
2. The load balance evaluates the request received and decides which server or resource should manage the request. A predefined load balancing algorithm considers factors like server capacity, server response time, number of active connections, and geographic location, for example.
3. After that, the load balance forwards the incoming traffic to the select server or resource which was decided from the previous step.
4. The server processes the request and sends it back to load balance.
5. Load balance receives the response from the server and sends it back to the caller.
The Usages of Load Balance:
- Improving website performance
Since load balance can distribute the incoming request among multiple servers, evicting overload on individual servers that way making faster response time for the request caller.
2. Ensuring high availability and reliability
By nature, distributing the requests among multiple servers load balance help to prevent a single point of failure. The load balance has the intelligence to redirect the traffic to the available server if it checks one server is failing or experiencing a deficient performance.
3. Scalability
Load balance can help easily scale the infrastructure as the traffic increases. As additional servers could be added to the load balance poll to fit the increase demand, this could be achieved without some effortless in infrastructure.
4. Redundance
The strategy to use load balance to maintain the redundant copies of data and services so this could reduce the risk of data loss, inconsistence, or service outages due to some hardware failure or other issues.
5. Network Optimization
By route the network traffic across multiple servers in different paths load balance optimize and reduce congestion in the network, improving the overall network performance.
6. Geographic Distribution
Load balance can be used to reach the nearest or best-performing server to the end user. This is especially useful for global services that can be reached from anywhere in the globe, so the load balance can be used to distribute the traffic to better option.
7. Application Performance
By redirecting the requests to specific applications, the load balance can ensure that each request receives the necessary resources to perform optimally.
8. Security
Load balance can protect against DDoS attacks making it harder to overwhelm a single target.
9. Cost saving
This can be achieved through effective utilization and efficient workload distribution by load balancers, resulting in hardware and infrastructure optimization.
10. Load testing
Load balance can be configurated to simulate high incoming traffic to evaluate the application performance and identify the application bottle necks.
Conclusion
Load balancing plays a crucial role in optimizing system performance and ensuring high availability. By evenly distributing incoming requests across multiple servers, load balancing reduces load times and prevents any single server from becoming a bottleneck. It offers benefits such as improved website performance, scalability, network optimization, geographic distribution, and enhanced application performance. Load balancing also provides security against DDoS attacks and helps achieve cost savings through efficient workload distribution. By understanding the key concepts and usages of load balancing, system designers can effectively implement this critical component to enhance their applications’ responsiveness and reliability.
In the next article I will bring some of the algorithm used in load balance which has different purposes and the pros and cons.
I hope you enjoy this article, feel free to make your comment about it or give any suggestions.
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