Managing HP Serviceguard A.11.20.20 for Linux, May 2013

The following are the failure/recovery detection times for
different values of Network Polling Interval (NPI) for an IP
monitored Ethernet interface:
Table 5 Failure Recovery Detection Times for an IP Monitored
Ethernet Interface
Failure/Recovery Detection Times (in seconds)
Values of
Network Polling
Interval (NPI) (in
seconds)
~ NPI x 8 - NPI x 91
~ NPI x 4 - NPI x 52
~ NPI x 3 - NPI x 43
~ NPI x 2 - NPI x 34 to 8
~ NPI x 1- NPI x 2>=8
IMPORTANT: HP strongly recommends using the default.
Changing this value can affect how quickly the link-level
and IP-level monitors detect a network failure. See
“Monitoring LAN Interfaces and Detecting Failure: Link Level”
(page 66).
Can be changed while the cluster is running.
CONFIGURED_IO_TIMEOUT_EXTENSION The number of microseconds by which to increase the time
Serviceguard waits after detecting a node failure, so as to
ensure that all pending I/O on the failed node has ceased.
This parameter must be set in the following cases.
• For extended-distance clusters using software mirroring
across data centers over links between iFCP switches;
it must be set to the switches' maximum R_A_TOV value.
NOTE: CONFIGURED_IO_TIMEOUT_EXTENSION
is supported only with iFCP switches that allow you to
get their R_A_TOV value.
• For switches and routers connecting an NFS server and
cluster-node clients that can run packages using the
NFS-mounted file system; see “Planning for
NFS-mounted File Systems” (page 106).
To set the value for the
CONFIGURED_IO_TIMEOUT_EXTENSION, you must
first determine the Maximum Bridge Transit Delay
(MBTD) for each switch and router. The value should
be in the vendors' documentation. Set the
CONFIGURED_IO_TIMEOUT_EXTENSION to the sum
of the values for the switches and routers. If there is
more than one possible path between the NFS server
4.7 Cluster Configuration Planning 101