Server load balancing increases the efficiency of your server farm, keeping applications running if servers go down, and forwarding computing requests to the most appropriate server.
Increase the performance of your server farm by running distributed applications where the load balancer forwards end-users requests to application servers based on pre-defined rules & policies. This reduces server application latency while reducing bottlenecks, enabling computing resources effectively.
Load balancers allows new virtual and/or physical server to be added transparently, maximizing flexibility, and allowing server applications to scale without disruption. No need to direct traffic on the client side to a new application server, the load balancer handles all server requests and distributes them to the most appropriate resources.
Load balancers can make things such as server failures occur without any disruption to applications or services. In the event of server failure, the load balancer simply redistributes future requests to the remaining server resources. This capability
Availability can be further maximized with an active/standby configuration, in which two load balancers handle traffic, and if one goes down, the remaining one handles the traffic, eliminating downtime if a load balancer fails.
Persistence is needed in certain server application that manage the client state on the server side. In addition to preserving session integrity when needed (such as traditional online “shopping carts”), stickiness or persistence can be employed to keep a particular user on the same server for all requests for a pre-determined period.
Layer 4 persistence employs user persistence by tracking users via the source IP address where the request is coming from. Unfortunately, NAT technology and the fact that many users site behind a farm of proxy servers that can change source IP for that user during each request, Layer 4 persistence has proven to be unreliable for many applications.
Layer 7 persistence leverages “cookie” technology to track user sessions, maintaining client state and transaction integrity. Many new applications are using SSL technology to maximize security, but SSL is a compute-intensive technology. Some load balancers now feature SSL offloading, allowing the load balancer to decrypt SSL data and forward it onto the appropriate server.
KEMP Technologies is the only vendor that provides Layer 7 persistence and content switching at a low-cost. For Layer 7 technology, you normally need to buy expensive hardware from Barracuda, Alteon or F5.