After you configure a basic load balancing setup, you can make a number of modifications to it so that it distributes load exactly as you need. The load balancing feature is complex. You can modify the basic elements by changing the load balancing algorithm, configuring load balancing groups and using them to create your load balancing configuration, configuring persistent client-server connections, configuring the redirection mode, and assigning different weights to different services that have different capacities.
The default load balancing algorithm on the NetScaler appliance is the least connection method, which configures the appliance to send each incoming connection to the service that is currently handling the fewest connections. You can specify different load balancing algorithms, each of which is suited to different conditions.
To accommodate applications such as shopping carts, which require that all requests from the same user be directed to the same server, you can configure the appliance to maintain persistent connections between clients and servers. You can also specify persistence for a group of virtual servers, causing the appliance to direct individual client requests to the same service regardless of which virtual server in the group receives the client request.
You can enable and configure the redirection mode that the appliance uses when redirecting user requests, choosing between IP-based and MAC-based forwarding. You can assign weights to different services, specifying what percentage of incoming load should be directed to each service, so that you can include servers with different capacities in the same load balancing setup without overloading the lower-capacity servers or allowing the higher-capacity servers to sit idle.