HP Serviceguard manual Choosing Switching and Failover Behavior, Package Failover Behavior

This paper includes instructions for setting up a sample package that uses an NFS-imported file system.

See also the description of fs_name (page 251), fs_type (page 251), and the other file system-related package parameters.

Planning for Expansion

You can add packages to a running cluster. This process is described in “Cluster and Package Maintenance” (page 261).

When adding packages, be sure not to exceed the value of max_configured_packages as defined in the cluster configuration file; see “Cluster Configuration Parameters ” (page 109). You can modify this parameter while the cluster is running if you need to.

Choosing Switching and Failover Behavior

To determine the failover behavior of a failover package (see “Package Types” (page 50)), you define the policy that governs where Serviceguard will automatically start up a package that is not running. In addition, you define a failback policy that determines whether a package will be automatically returned to its primary node when that is possible.

The following table describes different types of failover behavior and the settings in the package configuration file that determine each behavior. See “Package Parameter Explanations” (page 233) for more information.

Table 7 Package Failover Behavior

Switching Behavior

Package switches normally after detection of service, network, generic resource failure, or EMS failure, or when a configured resource dependency is not met. Halt script runs before switch takes place. (Default)

Package fails over to the node with the fewest active packages.

Package fails over to the node that is next on the list of nodes. (Default)

Package is automatically halted and restarted on its primary node if the primary node is available and the package is running on a non-primary node.

Parameters in Configuration File

•node_fail_fast_enabled set to no. (Default)

•service_fail_fast_enabled set to NO for all services. (Default)

•auto_run set to yes for the package. (Default)

•failover_policy set to min_package_node.

•failover_policy set to configured_node. (Default)

•failback_policy set to automatic.

If desired, package must be manually returned to its primary node if it is running on a non-primary node.

All packages switch following a system reset (an immediate halt without a graceful shutdown) on the node when a specific service fails. Halt scripts are not run.

•failback_policy set to manual. (Default)

•failover_policy set to configured_node. (Default)

•service_fail_fast_enabled set to yes for a specific service.

•auto_run set to yes for all packages.

All packages switch following a system reset on the node when any service fails. An attempt is first made to reboot the system prior to the system reset.

•service_fail_fast_enabled set to yes for all services.

•auto_run set to yes for all packages.

Failover packages can be also configured so that IP addresses switch from a failed LAN card to a standby LAN card on the same node and the same physical subnet. To manage this behavior, use the parameter local_lan_failover_allowed (page 241) in the package configuration file. (yes, meaning enabled, is the default.)

132 Planning and Documenting an HA Cluster