Managing HP Serviceguard A.11.20.00 for Linux, June 2012

NOTE: This is the default if cmquerycl detects a gateway for the subnet in question; see SUBNET
under “Cluster Configuration Parameters ” (page 80) for more information.
IMPORTANT: By default, 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
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
NOTE: This is not the default. If cmquerycl does not detect a gateway for the subnet in question,
it sets IP_MONITOR to OFF, disabling IP-level polling for this subnet; if it does detect a gateway,
it populates POLLING_TARGET, enabling target polling. See SUBNET under “Cluster Configuration
Parameters ” (page 80) for more information.
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
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 80) for more information.
Failure and Recovery Detection Times
With the default NETWORK_POLLING_INTERVAL of 2 seconds (see “Cluster Configuration
Parameters ” (page 80)), 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 61).
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.
60 Understanding Serviceguard Software Components