Business Continuity

Service Downtime can be a catastrophic event for many organizations. Two techniques - Server Load Balancing and Global Server Load Balancing are used to reduce the risk that infrastructure failure will cause downtime for your business-critical services.

Server Load Balancing

Service Load Balancing is used within a datacenter to load-balance traffic across local servers. For more details, please see Zeus Traffic Manager.

Global Server Load Balancing

Global Server Load Balancing (GSLB) systems allow an organization to host services from multiple different service points ('datacenters').  Disaster Recovery mode provides failover from a primary datacenter to a secondary one if the primary were to fail.

Disaster Recovery in more detail...

Zeus solutions continually test the availability and correct operation of the services running in each datacenter. Customizable health monitors run a range of tests, and verify external connectivity.

For each service, datacenters can be chained in the order they should be used. The first datacenter in the chain is used by all clients unless a monitor indicates that it has failed. Upon failure, the service fails over to the next datacenter in the chain.

When the first datacenter recovers, it will not failover back to that datacenter. It will continue to send clients to the subsequent datacenter until it is explicitly instructed to fail back to the primary. This allows an administrator to resynchronize data back to the recovered datacenter before making it live again.

For stateless applications, such as simple content serving, the optional 'Automatic Failback' mode will immediately make the primary datacenter active again when it recovers.

Benefits

The benefit of an active-passive load balancing mode is that it gives a very deterministic, controllable disaster recovery solution, ideally suited for complex, stateful applications.