Using Serviceguard Extension for RAC, 6th Edition, April 2008

• If more than one instance of pkgA is running in the cluster and SubnetA fails on
one of the nodes where the instance of pkgA is running, the failure is handled by
halting the instance of pkgA on the node where the subnet has failed.
• If pkgA is running on only one node of the cluster and SubnetA fails on that node,
pkgA will continue to run on that node after the failure.
• If pkgA runs on all nodes of the cluster and SubnetA fails on all nodes of the
cluster, the failure is handled by halting all but one instance of pkgA. Where the
instance of pkgA will be left running is randomly determined.
The following describes the behavior of cluster interconnect subnet monitoring feature
under the following scenarios:
• For a multi-node package with CLUSTER_INTERCONNECT_SUBNET configured,
upon an explicit request to start the package on a node, no attempt to start the
package instance on that node will be made if the subnet is not up on that node.
• If a multi-node package with CLUSTER_INTERCONNECT_SUBNET configured is
running on only one node of the cluster, with the subnet that it monitors is down
on all nodes of the cluster, the restoration of the subnet on any other node does
not affect the running instance. No attempt will be made automatically to start the
package instance on the restored node. An attempt to start the instance of the
package on the restored node will be made, if the user explicitly tries to start the
package instance.
• If a multi-node package with CLUSTER_INTERCONNECT_SUBNET is running on
more than one node of the cluster, upon a failure of the subnet on all nodes where
the package is running, all but one package instance will be halted one by one.
Additionally if NODE_FAIL_FAST_ENABLEDis set to “YES” for such a package,
all but one node will be brought down one by one, that is one node will be brought
down, cluster reformation will happen, another node will be brought down, cluster
reformation will happen and so on till one node remains in the cluster.
NOTE: The CLUSTER_INTERCONNECT_SUBNET parameter is available only for
use with multi-node packages.
For more information on the Cluster Interconnect Subnet Monitoring feature, refer to
chapter 2, section “Cluster Communication Network Monitoring” (page 47). This
section describes various network configurations for cluster communications in an
SGeRAC/10g RAC cluster, and how the package configuration parameter
CLUSTER_INTERCONNECT_SUBNET can be used to recover from Oracle Cluster
Communications network failures.
Overview of SGeRAC and Oracle 9i RAC
This section describes some of the central components and functionality for SGeRAC
and Oracle 9i RAC.
28 Introduction to Serviceguard Extension for RAC