HP Serviceguard for Linux Version A.11.19 Release Notes, July 2009

• A minimum of two heartbeat paths must be configured for each cluster node.
• There must be less than 200 milliseconds of latency in the heartbeat network.
• Each heartbeat subnet on each node must be physically routed separately to the
heartbeat subnet on another node; that is, each heartbeat path must be physically
separate:
— The heartbeats must be statically routed; static route entries must be configured
on each node to route the heartbeats through different paths.
— Failure of a single router must not affect both heartbeats at the same time.
• Deploying applications in this environment requires careful consideration; see
“Implications for Application Deployment” in Chapter 4 of Managing Serviceguard
for Linux.
• 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.
• You cannot use Serviceguard Manager to configure a cross-subnet cluster or
package.
• Cross-subnet configurations are not supported in IPv6-only or mixed mode clusters
(see “New Support for IPv6” (page 15) for information about these modes).
• Cross-subnet configurations are not supported by the SGeSAP Toolkit.
For More Information
For more information, see the following documents on docs.hp.com under High
Availability -> Serviceguard for Linux.
For the details of configuring the cluster and packages in a cross-subnet context, see
the following sections in Managing Serviceguard for Linux: “Obtaining Cross-Subnet
Information” in Chapter 5, “About Cross-Subnet Failover” in Chapter 4, and (for legacy
packages only) “Configuring Cross-Subnet Failover” in Chapter 7.
For discussion and illustration of supported configurations, and also potential
mis-configurations, see the white paper Technical Considerations for Creating a Serviceguard
Cluster that Spans Multiple IP Subnets, which you can find at the same address.
30 Serviceguard for Linux Version A.11.19 Release Notes