Load Balancing Algorithm

Static Algorithms

Round robin

Distribute requests evenly in each server

Pros

• Easy to do
• Make sure all the requests get routed properly
  Cons
• If one server is temporary unavailable and get back up again, caused inbalancing in distribution
• The routing is not necessary optimised for the connection

Sticky round robin

Same request goes to the same servers.

Pros:

• Server contains information for the relevant requests, hence make it more suitable to handle requests from the same server.

Cons:

• Could happen unbalance distribution where one users make more requests than the other users.

Weighted round robin

Each server has a weight of distribution and request can distribute there.

Pros:

• Have more control of the distribution
  Cons:
• Weighted attributes needs to be monitor and configure manually

IP/URL Hash

We route each request IP to the corresponding server.

Pros:

• Provide a control over which IP goes to which server
  Cons:
• Unbalance distribution
• Hash function is difficult to calculate

Dynamic algorithms

Least connections

Routes to the server that currently has the least connection

Pros:

• Properly distribute all the requests to server.
• Dynamically adjusted base on the need

Cons:

• Need to monitor the connections for each server which requires resources.

Least latency

Route to the nearest server based on the user latency.

Pros:

• Highly adaptive and reactive
  Cons:
• Introduce complexity
• Constant monitoring
• Doesnt monitor how many requests the server currently have.