HP Serviceguard manual Reporting Link-Level and IP-Level Failures, Constraints and Limitations

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 76).

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 70) 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 69) and “Monitoring LAN Interfaces and Detecting Failure: IP Level” (page 73) for information about each level of monitoring. Any given failure may occur at the link level or the IP level. In addition, local switching may occur, that is, a switch to a standby LAN card if one has been configured; see “Local Switching ” (page 70).

The following examples show when and how a link-level failure is differentiated from an IP-level failure in the output of cmviewcl (1m).

As you can see, if local switching is configured, the difference is the keyword disabled, which appears in the tabular output, and is set to true in the line output, if the IP Monitor detects the failure. If local switching is not configured, the output is the same whether link-level or IP monitoring detects the failure.

Example 1: If Local Switching is Configured

If local switching is configured and a failure is detected by link-level monitoring, output from cmviewcl -vwill look like something like this:

Network_Parameters:
INTERFACE	STATUS	PATH	NAME
PRIMARY	down (Link and IP)	0/3/1/0	lan2
PRIMARY	up	0/5/1/0	lan3

cmviewcl -v-f line will report the same failure like this:

node:garyinterface:lan2status=down node:garyinterface:lan2local_switch_peer=lan1 node:garyinterface:lan2disabled=false node:garyinterface:lan2failure_type=link+ip

76 Understanding Serviceguard Software Components