Dispatcher High Availability Failover detection
 Technote (troubleshooting)
 
Problem(Abstract)
Dispatcher High Availability Failover detection
 
Resolving the problem
There are two possible scenarios where a failover occurs within Dispatcher High Availability.

In the first scenario, failover occurs due to reach targets. The two High Availability partners are continually in touch with each other through heartbeats, and they update one another on how many reach targets either one of them can ping. If the backup pings more reach targets than the primary, a failover occurs.

In the second scenario, failover occurs due to a loss of heartbeats. Heartbeats are sent by the active Dispatcher and are expected to be received by the standby Dispatcher every half second. If the standby Dispatcher fails to receive a heartbeat within 2 seconds, the failover begins. In this scenario, all heartbeats must break for a takeover from the standby Dispatcher to occur. In other words, when two heartbeat pairs are configured, both heartbeats must break.

To stabilize an High Availability environment and to avoid failover, it is recommended that you add more than one heartbeat pair.

 
 
Cross Reference information
Segment Product Component Platform Version Edition
Application Servers WebSphere Edge Server Load Balancer AIX, Linux, Solaris, Windows 2000, Windows NT Edge Server 2.0 GA, Edge Server 2.0 NLV, Edge Server 2.0 PTF1, Edge Server 2.0 PTF2, Edge Server 2.0.x
Application Servers Runtimes for Java Technology Java SDK
 
 


Document Information


Product categories: Software > Application Servers > Distributed Application & Web Servers > WebSphere Application Server > Edge Component
Operating system(s): Windows
Software version: 5.0
Software edition:
Reference #: 1079113
IBM Group: Software Group
Modified date: Oct 3, 2003