Managing Serviceguard Eighteenth Edition, September 2010

NOTE: This is the default if cmquerycl does not detect a gateway for the subnet in
question; it is equivalent to having no SUBNET entry for the subnet. See SUBNET under
“Cluster Configuration Parameters ” (page 143) for more information.
Failure and Recovery Detection Times
With the default NETWORK_POLLING_INTERVAL of 2 seconds (see “Cluster
Configuration Parameters ” (page 143)) the IP monitor will detect IP failures typically
within 8–10 seconds for Ethernet and within 16–18 seconds for InfiniBand. Similarly,
with the default NETWORK_POLLING_INTERVAL, the IP monitor will detect the
recovery of an IP address typically within 8–10 seconds for Ethernet and with 16–18
seconds for InfiniBand.
IMPORTANT: HP strongly recommends that you do not change the default
NETWORK_POLLING_INTERVAL value of 2 seconds.
See also “Reporting Link-Level and IP-Level Failures” (page 101).
Constraints and Limitations
• A subnet must be configured into the cluster in order to be monitored.
• Polling targets are not detected beyond the first-level router.
• Polling targets must accept and respond to ICMP (or ICMPv6) ECHO messages.
• A peer IP on the same subnet should not be a polling target because a node can
always ping itself.
• On an HP-UX system, an IP-level failure on the standby interface will not be
detected until the IP address fails over to the standby.
• On an HP-UX system, after the IP address fails over to the standby, the IP monitor
will not detect recovery on the primary interface.
The following constraints apply to peer polling when there are only two interfaces on
a subnet:
• If one interface fails, both interfaces and the entire subnet will be marked down
on each node, unless Local Switching (page 93) is configured and there is a working
standby.
• If the node that has one of the interfaces goes down, the subnet on the other node
will be marked down.
Reporting Link-Level and IP-Level Failures
Serviceguard detects both link-level and IP-level failures; see “Monitoring LAN
Interfaces and Detecting Failure: Link Level” (page 92) and “Monitoring LAN Interfaces
and Detecting Failure: IP Level” (page 98) for information about each level of
monitoring. Any given failure may occur at the link level or the IP level. In addition,
How the Network Manager Works 101