Managing HP Serviceguard A.12.00.00 for Linux, June 2014

The IP Monitor section of the cluster configuration file will look similar to the following for a subnet
on which IP monitoring is configured with target polling.
IMPORTANT: By default, the cmquerycl does not verify that the gateways it detects will work
correctly for monitoring. But if you use the -w full option, cmquerycl will validate them as
polling targets.
SUBNET 192.168.1.0
IP_MONITOR ON
POLLING_TARGET 192.168.1.254
By default, IP_MONITOR parameter is set to OFF. If a gateway is detected for the subnet in question,
it populates the POLLING_TARGET , which is commented out, and sets the IP_MONITOR parameter
to OFF.
SUBNET 192.168.1.0
IP_MONITOR OFF
#POLLING_TARGET 192.168.1.254
To configure a subnet for IP monitoring with peer polling, edit the IP Monitor section of the cluster
configuration file to look similar to this:
SUBNET 192.168.2.0
IP_MONITOR ON
The IP Monitor section of the cluster configuration file will look similar to the following in the case
of a subnet on which IP monitoring is disabled:
SUBNET 192.168.3.0
IP_MONITOR OFF
3.5.7.2.1 Failure and Recovery Detection Times
With the default NETWORK_POLLING_INTERVAL of 2 seconds (see “Cluster Configuration
Parameters” (page 89)), 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.
The minimum time for detecting a failure/recovery of an IP address is 8 seconds for Ethernet and
15 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 67).
3.5.7.3 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.
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 bonding 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.
• In a 2-node cluster, there is only a single peer for polling. When POLLING_TARGET is not
defined, if either of the nodes fail (For example, a node is rebooted or all the interfaces of a
66 Understanding Serviceguard Software Components