Basics about Static and Dynamic Load Balancing Methods
Today we are going to talk about the difference between the static and dynamic load balancing. In this article I will talk the basic difference between them.
Static Load Balancing
Static load balancing modes do not use node efficiency data to make distribution results. For example, Round Robin is a static load balancing mode that load balances connections among accessible nodes without calculating the comparative performance of those nodes.
Round Robin - Evenly distributes appeals to all available pool members.
Ratio - Ratio permits each server to be allocated a ratio value. This is beneficial for pool members that have better or inferior computing assets then others. Example : Ratio 3:2:1:1. Based upon 8 requests, 3 desires would go to 1, 2 to 2 then 1 to 1.
Below is the example with the BIP-IP LTM having Round-robin and Ratio static Load Balancing
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| Fig 1.1- Static Load Balancing |
Dynamic Load Balancing
Dynamic load balancing modes use node performance data to build load balancing results. For example, Minimum Connections is a dynamic load balancing mode that inspects the ratio of open connections to nodes across Virtual Servers, and then directs the connection appeal to the node with the least number of concurrent connections. Dynamic load balancing approaches are measured balancing methods that take the server performance into consideration.
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| Fig 1.2- Least and Fastest Dynamic Load Balancing |
Least Connections - Traffic is balanced to servers with the minimum total of current connections.
Fastest - Connections are distributed to pool members based upon server response time.
Observed - This method is the same as ratio but the ratio is assigned. Each ratio is estimated based upon the total number of connections presently active on each pool member. A pool member with a lower then average connection count is assigned a ratio of 3. A pool member with a higher than average count is given ratio of 2.
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| Fig 1.3- Observed and Predictive Dynamic Load Balancing |
Predictive - Predictive is similar to observed but ratios are allocated using much more assertive ratio values. A pool member with a lower then average connection count is assigned a ratio of 4. A pool member with a higher than average count is given ratio of 1.
