HP Serviceguard manual Redundant Ethernet Configuration, Redundant LANs

configured into the Serviceguard cluster, unless those IP addresses themselves will be immediately configured into the cluster as stationary IP addresses.

CAUTION: If you configure any address other than a stationary IP address on a Serviceguard network interface, it could collide with a relocatable package IP address assigned by Serviceguard. See “Stationary and Relocatable IP Addresses ” (page 67).

(Oracle VIPs are an exception to this rule; such configurations require the HP add-on product Serviceguard Extension for Oracle RAC).

◦Similarly, Serviceguard does not support using networking tools to move or reconfigure any IP addresses configured into the cluster.

Doing so leads to unpredictable results because the Serviceguard view of the configuration is different from the reality.

NOTE: If you will be using a cross-subnet configuration, see also the Restrictions (page 30) that apply specifically to such configurations.

Redundant Ethernet Configuration

The use of redundant network components is shown in Figure 4, which is an Ethernet configuration.

Figure 4 Redundant LANs

In the figure, a two-node Serviceguard cluster has one bridged net configured with both a primary and a standby LAN card for the data/heartbeat subnet (subnetA). Another LAN card provides an optional dedicated heartbeat LAN. Note that the primary and standby LAN segments are connected by a hub to provide a redundant data/heartbeat subnet. Each node has its own IP address for this subnet. In case of a failure of a primary LAN card for the data/heartbeat subnet, Serviceguard will perform a local switch to the standby LAN card on the same node.

Redundant heartbeat is provided by the primary LAN and the dedicated LAN which are both carrying the heartbeat. In Figure 4, local switching is not needed for the dedicated heartbeat LAN, since there is already a redundant path via the other subnet. In case of data congestion on the primary LAN, the dedicated heartbeat LAN will prevent a false diagnosis of heartbeat failure. Each node has its own IP address for the dedicated heartbeat LAN.

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