Saturday, September 15, 2007

Oracle Application Server : Load Balancer

Oracle Application Server : Load Balancer

Load Balancing is a technique used to spread work between many computers , processors , disks and other resouces in order to get optimal resource utilization and decreasing computing time.

Load Balancing technique are used across various application and system which are 24/7 to accomodate world wide access. Failure of one particular resource will not affect the availability of the system , Failover of the system will also not affect the availability of the system and moreover Failback of the system will be invisible to the end users when the Load Balancer techniques are well in place.

A Load Balancer is a virtual server which consists of virtual IP Address and Port , which internally talks to the other available real IP Address and Ports. Internal mapping make the Virtual IP Access to get load balanced towards the available resources.

Persistance in a concept where once a server is selected , subsequent request to the server from the client will not change and hit the same server. There are cases where sometimes an application need to maintain client state on a particular server , there are other possibilities on the Persistance usage with the Load Balancer , once such is that when the data is cached on a particular server and the requirement is that the client needs to get always hit the server which has been used previously to get connected. This internally boosts the performance of the server not getting the cache generated again. There are more features of Load Balancer which varies with the vendor

Scalability with the Load Balancer
When large internet based applications are considered they need to scale automatically based on the load. Most of the firewall algorithm supports the same. Some of them are Round Robin , Squid Cache Server , PHP Scripts and more.

What about Multiple Providers
When your internet application gets loaded and your provider is not able to hold the load , the application will fail finally. With the help of Load Balancer it is easy to configure Multiple Provider where it helps the application to be available with several provider where by keeping the system up and available 24/7.

Response Timeout
It is the time configured which indicated the failure of the physical server to respond. The most common way to get the timeout monitored is by pinging or by checking the port is open and active.

Tested LoadBalancer: The following are the some of the tested firewall that are found to be working good with version 10.1.2 and 10.1.3.
CAI Networks
Crescendo Networks

More information follow the link as the above information differ in future.

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