Load balancing methods

Last updated 17th January 2018

Objective

The new OVH Load Balancer service offers a variety of load balancing methods for your services. This process determines the way in which the OVH Load Balancer distributes the requests received by your servers.

This guide will provide an introduction to the various load balancing methods, and will explain how you can modify them.

Requirements

• You must be logged in to the OVH Control Panel.
• You need to have created a server farm.

Instructions

Different load balancing methods

Load balancing is used in server farms. This setting defines the way that requests are distributed between the servers within the farm.

To understand the basics of the OVH Load Balancer service, please refer to the Load Balancer Introduction.

Algorithm	Features
First	The first available server receives the connection. The server is chosen according to its ID, from smallest to largest.
LeastConn	Selects the server that has the lowest number of active connections. This setting is recommended for long sessions, with low levels of traffic. The RoundRobin algorithm is applied to groups of servers that have the same number of active connections.
RoundRobin	Selects the servers one after the other for each connection. This is the default algorithm.
Source	This algorithm hashes the source IP address, then divides the result by the number of servers currently running. The same source IP address will then still be redirected to the same server, provided that it continues to run.
URI	This algorithm hashes part or all of the URI, then divides the result by the number of servers currently running. The same URI will then still be redirected to the same server, provided that it continues to run.

Modify a server farm’s load balancing method via the Control Panel

• In the Server farms section (1), you will see the farms that have been created. You can edit them by clicking the three dots on the right-hand side (2), then Change:

In Advanced settings, you can modify your Load balancing method:

Once you have selected your preferred load balancing method, click Update, then Apply configuration in the yellow banner that appears:

Modify a server farm’s load balancing method via the API

You can modify the load balancing method settings by editing them in the server farm.

• View details on a server farm

With this call instruction, you can view details on a server farm if you know its ID. In this example, we will work on an HTTP farm:

Setting	Meaning
ServiceName*	Your Load Balancer service ID
farmId*	The farm’s ID number

Response (BackendHttp)	Meaning
farmId	The farm’s ID number
balance	Balance type currently set for the farm
zone	Name of the zone in which the farm is configured
port	Port used to contact the servers configured on the farm
probe	Type of probe currently configured on the farm
displayName	Name given to this farm
stickiness	Connection monitoring method currently set for the farm

• Modify a server farm’s load balancing method

With this call instruction, you can edit the settings of a server farm if you know its ID. In this example, we will work on an HTTP farm. To modify the balancing method, the BackendHttp.balance field must be updated with an available balancing method:

Setting	Meaning
ServiceName*	Your Load Balancer service ID
farmId*	The farm’s ID number
BackendHttp.balance	Preferred balancing method for this farm

• Apply the modifications

Setting	Meaning
ServiceName*	Your Load Balancer service ID
zone*	Name of the zone in which to deploy the configuration

Go further

Join our community of users on https://community.ovh.com/en/.

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