High Availability

For many environments that use it, NetScaler becoming unavailable means losing access to a fleet of web applications, and even access to the corporate network in the case of NetScaler Gateway deployments. So it is little wonder that, when NetScaler is deployed in an enterprise, it is always deployed in High Availability (HA) pairs.

In a properly set up HA pair environment, the standby NetScaler, which we refer to as the secondary in this chapter, jumps into action within milliseconds of detecting a failure and announces its intention to become the primary. If the network is fast in adapting itself to the change of ownership, traffic gets restored within seconds of the failure.

Note

There are several other ways of providing High Availability via NetScaler – HA over INC, Route Health Injection, and Clustering. The focus of this section is on the way that more than 90% of deployments use it, which is High Availability in Active-Standby over layer 2 connectivity.

In the next few...