Optimizing Failover Time in a Serviceguard Environment, June 2007

Conclusion

The total failover time in a Serviceguard cluster depends on many different factors and the interactions

between them. Serviceguard users can optimize failover time to help maximize the time applications

are available.

Optimizing failover time means finding a balance between waiting longer than needed to act and

acting too hastily. Less time spent in the failover process means less time packages are unavailable. If

a cluster detects failures quickly, it can re-form and restart its applications quickly. But if the timing is

set too aggressively, it can result in unnecessary—and possibly repeated—failovers, ultimately

decreasing overall availability.

The total time for failover includes a Serviceguard component and an application-dependent

component. Over-emphasis on optimizing only one component can result in higher unavailability.

To help reduce the time for the Serviceguard component, examine the settings for several timing

parameters, primarily NODE_TIMEOUT.

To reduce the time for application startup and recovery, examine the control script and each

application’s documentation.

Serviceguard Extension for Faster Failover, a product purchased separately, can further reduce

Serviceguard’s failover time to as little as 5 seconds. It is only supported with certain configurations.

For more information

To learn more about HP high-availability products and solutions, please visit:

www.hp.com/go/serviceguard

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06/2007