Managing HP Serviceguard for Linux, Tenth Edition, September 2012

Figure 25 Bonded NICs Configured for Load Balancing
Monitoring LAN Interfaces and Detecting Failure: Link Level
At regular intervals, determined by the NETWORK_POLLING_INTERVAL (see “Cluster
Configuration Parameters ” (page 103)), 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 79). When the link comes back up, Serviceguard marks the
interface, and all subnets running on it, as up.
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.
How the Network Manager Works 75