HP Serviceguard manual Enabling the Network Time Protocol, Tuning Network and Kernel Parameters

cluster node, they may also need to be changed on other cluster nodes that can run the same packages.

Enabling the Network Time Protocol

HP strongly recommends that you enable network time protocol (NTP) services on each node in the cluster. The use of NTP, which runs as a daemon process on each system, ensures that the system time on all nodes is consistent, resulting in consistent timestamps in log files and consistent behavior of message services. This ensures that applications running in the cluster are correctly synchronized. The NTP services daemon, xntpd, should be running on all nodes before you begin cluster configuration. The NTP configuration file is /etc/ntp.conf.

For information about configuring NTP services, refer to the HP-UX manual HP-UX Internet Services Administrator’s Guide posted at http://www.hp.com/go/hpux-networking-docs.

Tuning Network and Kernel Parameters

Serviceguard and its extension products, such as SGeSAP and SGeRAC, have been tested with default values of the network and kernel parameters supported by the ndd and kmtune utilities.

You may need to adjust these parameters for larger cluster configurations and applications.

•ndd is the network tuning utility. For more information, see the man page for ndd (1m)

•kmtune is the system tuning utility. For more information, see the man page for kmtune (1m).

Make adjustments with care, and if you experience problems, return the parameters to their default values.

NOTE: If you contact HP support regarding Serviceguard or networking, please be sure to mention any parameters that have been changed from their defaults.

Serviceguard has also been tested with non-default values for these network parameters:

•ip6_nd_dad_solicit_count — This network parameter enables the Duplicate Address Detection feature for IPv6 addresses. You can find more information l under “IPv6 Relocatable Address and Duplicate Address Detection Feature” (page 381).

•tcp_keepalive_interval — This network parameter controls the length of time the node will allow an unused network socket to exist before reclaiming its resources so they can be reused.

The following requirements must be met:

◦The maximum value for tcp_keepalive_interval is 7200000 (2 hours, the HP-UX default value).

◦The minimum value for tcp_keepalive_interval is 60000 (60 seconds).

◦The tcp_keepalive_interval value must be set on a node before Serviceguard is started on that node. This can be done by configuring the new tcp_keepalive_interval in the /etc/rc.config.d/nddconf file, which will automatically set any ndd parameters at system boot time.

◦The tcp_keepalive_interval value must be the same for all nodes in the cluster.

•ip_strong_es_model — This network parameter controls support for the strong end-system model, which prevents a system from acting as a router. For more information about this

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