Managing HP Serviceguard A.11.20.10 for Linux, December 2012

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 66).

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

node are down), IP monitoring fails and all the subnets are marked down on the operational

node. This results in failure of packages running on the operational node.

Therefore, peer polling is not suitable when there is only a single peer as exists in a 2-node

cluster. In such scenarios, a polling target should always be defined so that a single LAN

failure does not affect polling of other LANs.

3.5.8 Reporting Link-Level and IP-Level Failures

Any given failure may occur at the link level or the IP level; a failure is reported slightly differently

in the output of cmviewcl (1m) depending on whether link-level or IP monitoring detects the

failure.

If a failure is detected at the link level, output from cmviewcl -v will look like something like

this:

Network_Parameters:

INTERFACE STATUS PATH NAME

PRIMARY down (Link and IP) 0/3/1/0 eth2

PRIMARY up 0/5/1/0 eth3

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

node:gary|interface:lan2|status=down

node:gary|interface:lan2|disabled=false

node:gary|interface:lan2|failure_type=link+ip

If a failure is detected by IP monitoring, output from cmviewcl -v will look like something like