Managing HP Serviceguard A.11.20.10 for Linux, December 2012

on-board LAN interfaces) must be used in any combination of channel bonds to avoid a single
point of failure for heartbeat connections.
3.5.5 Bonding for Load Balancing
It is also possible to configure bonds in load balancing mode, which allows all slaves to transmit
data in parallel, in an active/active arrangement. In this case, high availability is provided by the
fact that the bond still continues to function (with less throughput) if one of the component LANs
should fail. The user should check the Bonding documentation to determine if the hardware
configuration must use Ethernet switches such as the HP Procurve switch, which supports trunking
of switch ports. The bonding driver configuration must specify mode 0 for the bond type.
An example of this type of configuration is shown in Figure 25.
Figure 25 Bonded NICs Configured for Load Balancing
3.5.6 Monitoring LAN Interfaces and Detecting Failure: Link Level
At regular intervals, determined by the NETWORK_POLLING_INTERVAL (see “Cluster Configuration
Parameters ” (page 86)), Serviceguard polls all the network interface cards specified in the cluster
configuration file (both bonded and non-bonded). If the link status of an interface is down,
Serviceguard marks the interface, and all subnets running on it, as down; this is shown in the output
of cmviewcl (1m); see “Reporting Link-Level and IP-Level Failures” (page 66). When the link
comes back up, Serviceguard marks the interface, and all subnets running on it, as up.
3.5.7 Monitoring LAN Interfaces and Detecting Failure: IP Level
Serviceguard can also monitor the IP level, checking Layer 3 health and connectivity for both IPv4
and IPv6 subnets. This is done by the IP Monitor, which is configurable: you can enable IP monitoring
for any subnet configured into the cluster, but you do not have to monitor any. You can configure
IP monitoring for a subnet, or turn off monitoring, while the cluster is running.
The IP Monitor:
3.5 How the Network Manager Works 63