HP Serviceguard A.11.20- Managing Serviceguard Twentieth Edition, August 2011

IP addresses are configured only on each primary network interface card; standby cards are not
configured with an IP address. Multiple IPv4 addresses on the same network card must belong to
the same IP subnet.
CAUTION: HP strongly recommends that you add relocatable addresses to packages only by
editing ip_address (page 243) in the package configuration file (or IP [] entries in the control
script of a legacy package) and running cmapplyconf (1m).
Load Sharing
Serviceguard allows you to configure several services into a single package, sharing a single IP
address; in that case all those services will fail over when the package does. If you want to be
able to load-balance services (that is, move a specific service to a less loaded system when
necessary) you can do so by putting each service in its own package and giving it a unique IP
address.
Monitoring LAN Interfaces and Detecting Failure: Link Level
At regular intervals, determined by the NETWORK_POLLING_INTERVAL (see “Cluster Configuration
Parameters ” (page 109)) Serviceguard polls all the network interface cards specified in the cluster
configuration file. Network failures are detected within each single node in the following manner.
One interface on the node is assigned to be the poller. The poller will poll the other primary and
standby interfaces in the same bridged net on that node to see whether they are still healthy.
Normally, the poller is a standby interface; if there are no standby interfaces in a bridged net, the
primary interface is assigned the polling task. (Bridged nets are explained under “Redundant
Network Components ” (page 28) in Chapter 2.)
The polling interface sends LAN packets to all other interfaces in the node that are on the same
bridged net and receives packets back from them.
Whenever a LAN driver reports an error, Serviceguard immediately declares that the card is bad
and performs a local switch, if applicable. For example, when the card fails to send, Serviceguard
will immediately receive an error notification and it will mark the card as down. See “Reporting
Link-Level and IP-Level Failures” (page 76).
Serviceguard Network Manager also looks at the numerical counts of packets sent and received
on an interface to determine if a card is having a problem. There are two ways Serviceguard can
handle the counts of packets sent and received. In the cluster configuration file, choose one of the
following values for the NETWORK_FAILURE_DETECTION parameter:
NOTE: For a full discussion, see the white paper Serviceguard Network Manager: Inbound
Failure Detection Enhancement at http://www.hp.com/go/hpux-serviceguard-docs.
• INOUT: When both the inbound and outbound counts stop incrementing for a certain amount
of time, Serviceguard will declare the card as bad. (Serviceguard calculates the time depending
on the type of LAN card.) Serviceguard will not declare the card as bad if only the inbound
or only the outbound count stops incrementing. Both must stop. This is the default.
• INONLY_OR_INOUT: This option will also declare the card as bad if both inbound and
outbound counts stop incrementing. However, it will also declare it as bad if only the inbound
count stops.
This option is not suitable for all environments. Before choosing it, be sure these conditions
are met:
◦ All bridged nets in the cluster should have more than two interfaces each.
◦ Each primary interface should have at least one standby interface, and it should be
connected to a standby switch.
How the Network Manager Works 69