Introduction of Load Balancer with example

In this article we learn what is load balancer, feature of load balancer and different type of algorithms used by a load balancer to distribute load traffic to the backend servers.

Load balancer has a feature to distribute load traffic to the backend servers. It is used to increase performance ,scalability and availability to access the service in the large traffic environment.

Normally load balancer is used to load traffic to the backend servers. Lets take an example if in an organization existing web server is overloaded by hitting huge no of traffic into the server, to fast the processing speed of the web server we need to add extra one or many web server to access web portal from the outside world. Now we place the load balancer top of the web servers to distribute traffic to all the web servers equally.

Introduction of Load Balancer with example

Feature of Load Balancer

Load balancer has one feature which is it checks periodically server health. If a server failed the load balancer detect the problem and bypass the server and allocate the entire load to the other live server to maintain the high availability. we can manage logical server from the load balancer.

Other feature is that persistency. It provides persistence feature to allow user to connect their connection to the same server. this feature is very helpful when we are taking about ecommerce site. When users purchasing some online things via online shopping cart they are using same server though this feature of load balancer.

Other feature is that cookies persistence. when user login a website load balancer sent the cookies to end user system .user can surfing website without relogin but it has time frame.when it is expired user has to login again to access the website.

Algorithms of Load Balancer

Round robin : Normally it is used in the load balancer to distribute traffic to all servers equally. First connection send to the first server and next connection send to the next server and so on.

Shortest path: it calculates the path matric which path is short to reach the server.

Server weight:server weight assigns to all servers and traffic is distributed to the servers according against their assign value. if server1 has a value which is 1 and server2 has a value which is 3 then load balancer sends 3 times more traffic to server2.

Least connection: load balancer send the traffic to the server which has lowest no of open connection.