Load Balancing Method Overview

Load Balancing Method Overview

Big IP F5 uses various types of load balancing methods, which directs how traffic and connections are distributed across pool members.

All different types of load balancing method are categorized in two parts:

• Static Load balancing
• Dynamic Load balancing

Let’s discuss each type of load balancing one by one.

Static Load Balancing

This method distributes the traffic and connections based on pre-defined pattern, and does not consider, how end server performance are. In this methods, to check the server health, BIG-IP F5 checks the health monitor data, and if Node or pool member is marked as offline, F5 do not send traffic to them.

There are two types of Load Balancing Methods available:

• Round Robin
• Ratio or Weighted Round Robin

Round Robin

In this Method, F5 distributes the traffic and connection evenly between all available pool members. This Method is suitable only when we have equal performance servers hosing applications.

Ratio or Weighted Round Robin

This is also called Weighted Round Robin and it distributes the connection, based on ration defined by user in F5.

This method is used when we have server of different performance capabilities. This method uses the ratio to load balance the connection in round robin fashion.

Let’s suppose , we have has pool in which we have two fast server and two slow performance server , due to which we have defined the ration like : 3:3:1:1. Now Server 1, server 2 will get 3 connections and server 3 and 4 will get one connection each based on round robin fashion.

If we do not define any ratio, it will be by default 1.

Dynamic Load Balancing

Dynamic Load balancing method distribute the load, to each pool members based on Servers performance or with some other metrics. Using this type of load balancing method, load of the serves can be different during certain time periods.

Below are some dynamic Load Balancing methods:

• Least Connection
• Fastest
• Least Sessions
• Ratio Connection
• Ratio Least Connection
• Weighted Least Connection
• Observed
• Predictive
• Dynamic Ratio

Least Connection

In this method, F5 distributes the connection based on current active connection count between F5 Device and end-Servers. If all Servers will have same number of connections with F5, the connection will be distributed in round-robin fashion. This type of load balancing method is used for long-lived connections like FTP, or SSH.

In this method, only active connection will be counted, idle Connection will not be counted.