Load Balancing Brick

Univ. of Hawaii - ITS Technical Architecture - Brick   

Load Balancing

Primary Architect: Michael Hodges

Description:   

 A load balancer is a device that distributes application or system traffic across a number of servers.  Load Balancing provides for redundancy and for horizontal scalability.  Redundancy helps ensure that an application is resilient to failures.  Horizontal scalability allows for capacity to be expanded by the addition of application instances.  Load Balancing can be accomplished with dedicated hardware appliances or with software.

Background:

• Traditionally, ITS has used load balances in an “active/passive” configuration.  In this model, if the active environment becomes unavailable, processing is handed off to the passive (secondary) environment.

• ITS has also used “round robin” load balancing for some applications.  This is a simple model where load is balanced in the order that requests come in. This technique has some value, but can still result in unbalanced situations.

• In the future ITS will rely more and more on advanced balancing features. Advanced balancing is more intelligent about where connections are routed to better ensure that load is equally balanced across environments.  For example, if one server has high CPU utilization, load balancing may focus connections on the other environment.

Emerging Trends:

• Vendors are augmenting application load balancers with additional software modules, usually at additional cost, that provide additional functionality, for example:

• Direct users to the nearest data center to provide the best application experience and to secure DNS infrastructure from attacks.

• Provide IP intelligence services  to increase data center efficiency by blocking malicious activity at the earliest point.

• Provide policy-based control over who is on the network and what applications they are allowed to use.

• Cloud based solutions provide various balancing options

Change History

• Approved October 2016

 Definitions