Managing Serviceguard A.11.20, March 2013

• You must not set the HP-UX network parameter ip_strong_es_model in a cross-subnet
configuration. Leave it set to the default (0, meaning disabled); Serviceguard does not support
enabling it for cross-subnet configurations. For more information about this parameter, see
“Tuning Network and Kernel Parameters” (page 176) and “Using a Relocatable Address as
the Source Address for an Application that is Bound to INADDR_ANY” (page 355).
• Deploying applications in this environment requires careful consideration; see “Implications
for Application Deployment” (page 161).
• cmrunnode will fail if the “hostname LAN” is down on the node in question. (“Hostname
LAN” refers to the public LAN on which the IP address that the node’s hostname resolves to
is configured).
• If a monitored_subnet is configured for PARTIAL monitored_subnet_access in a
package’s configuration file, it must be configured on at least one of the nodes on the
node_name list for that package. Conversely, if all of the subnets that are being monitored
for this package are configured for PARTIAL access, each node on the node_name list must
have at least one of these subnets configured.
◦ As in other configurations, a package will not start on a node unless the subnets configured
on that node, and specified in the package configuration file as monitored subnets, are
up.
NOTE: See also the Rules and Restrictions (page 28) that apply to all cluster networking
configurations.
For More Information
For more information on the details of configuring the cluster and packages in a cross-subnet
context, see “Obtaining Cross-Subnet Information” (page 195), “About Cross-Subnet Failover”
(page 160) and (for legacy packages only) “Configuring Cross-Subnet Failover” (page 314).
See also the white paper Technical Considerations for Creating a Serviceguard Cluster that Spans
Multiple IP Subnets, which you can find at the address below. This paper discusses and illustrates
supported configurations, and also potential mis-configurations.
IMPORTANT: Although cross-subnet topology can be implemented on a single site, it is most
commonly used by extended-distance clusters, and specifically site-aware disaster-tolerant clusters,
which require Metrocluster (HP add-on software).
Design and configuration of such clusters are covered in the disaster-tolerant documentation
delivered with Serviceguard. For more information, see the following documents under http://
www.hp.com/go/hpux-serviceguard-docs:
• Understanding and Designing Serviceguard Disaster Tolerant Architectures
• Designing Disaster Tolerant HA Clusters Using Metrocluster and Continentalclusters
• The white paper Configuration and Administration of Oracle 10g R2 RAC Database in HP
Metrocluster
Replacing Failed Network Cards
Depending on the system configuration, it is possible to replace failed network cards while the
cluster is running. The process is described under “Replacing LAN or Fibre Channel Cards” in the
chapter “Troubleshooting Your Cluster.” With some restrictions, you can also add and delete LAN
interfaces to and from the cluster configuration while the cluster is running; see “Changing the
Cluster Networking Configuration while the Cluster Is Running” (page 302).
Redundant Network Components 31