As the name suggests, load balancing refers to efficiently distributing server traffic over a group of connected servers, also known as a server farm or a server pool.
There are a lot of parallel requests coming in from users and clients alike, and the website has to be able to process thousands, if not millions, of them concurrently at a time and return the correct text, images, video, or application data, all in a fast and reliable manner. Typically, to scale up to meet these high volumes cost-effectively, the best practices of modern computing require the addition of more servers.
As the “traffic cop,” load balancers sit in front of your servers, directing client requests between all the servers that can fulfill those requests. The load balancer ensures that no one server is overworked, which could result in performance degradation. It ensures that all servers’ speed and capacity utilization are maximized and that no one server is overloaded. The load balancer ensures that traffic is routed to the remaining servers if one of the servers goes down. The load balancer automatically starts sending requests to the new server when it is added to the server group by adding it to the list of servers.
How do Load Balancers work?
To prevent traffic from being routed to servers unable to fulfill requests, load balancers use sophisticated algorithms to detect the health of backend servers. The purpose of a load balancer is to manage the traffic going to different web servers within a resource pool, regardless of whether it’s a hardware or software load balancer or what algorithm it uses to ensure that no single server becomes overworked and, therefore, unreliable due to its excessive workload. As a result, the server response time will be minimized, and the throughput will be maximized.
Often, load balancing is compared to the role of a traffic cop since it is responsible for systematically routing requests to the most appropriate locations at any given moment in time, thereby avoiding costly bottlenecks and preventative incidents.
What are some of the standard Load Balancing solutions?
A load balancer, or the ADC that includes it, will follow a set of algorithms to determine how requests will be distributed across the server farm. Again, there are plenty of options regarding this matter, from the very simple to the very complex.
Round robin load balancing
It is a simple load balancing solution for directing clients to a different server based on a rotational list when a client accesses the virtual server. However, despite its ease of implementation, load balancers fail to factor in the existing load on a server. As a result, the server may become overloaded with processor-intensive requests if it receives many requests.
Least response time method
The least response time method is more sophisticated for monitoring health data because it relies on the server’s response time to a health monitoring request. The overall expected user experience is how fast the server responds. Some load balancers may also consider the number of active connections on each server.
Least connection method
The least connection method considers the current load on the server, while the round-robin does not (only its position in rotation), resulting in considerably superior performance. In addition, requests will be sent to the server with the least number of active connections when using the least connection method.
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