Managing HP Serviceguard for Linux, Sixth Edition, August 2006

Understanding Serviceguard Software Components
How the Package Manager Works
Chapter 3 55
On Combining Failover and Failback Policies
Combining a FAILOVER_POLICY of MIN_PACKAGE_NODE with a
FAILBACK_POLICY of AUTOMATIC can result in a package’s running on a
node where you did not expect it to run, since the node running the
fewest packages will probably not be the same host every time a failover
occurs.
Choosing Package Failover Behavior
To determine failover behavior, you can define a package failover policy
that governs which nodes will automatically start up a package that is
not running. In addition, you can 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 ASCII package configuration file that determine each
behavior.
Table 3-3 Package Failover Behavior
Switching Behavior Parameters in ASCII File
Package switches normally after
detection of service or network failure.
Halt script runs before switch takes
place. (Default)
• 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)
Package fails over to the node with the
fewest active packages.
• FAILOVER_POLICY set to
MIN_PACKAGE_NODE.
Package fails over to the node that is next
on the list of nodes. (Default)
• FAILOVER_POLICY set to
CONFIGURED_NODE. (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.
• FAILBACK_POLICY set to AUTOMATIC.