Managing Serviceguard Eighteenth Edition, September 2010

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 299) 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 143)) 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 38) 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 101).
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 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
92 Understanding Serviceguard Software Components