Technical data

Using DNS to Balance Work Load
6.5 Configuring the Load Broker
6.5 Configuring the Load Broker
To configure the load broker, edit the file TCPIP$LBROKER_CONF.TEMPLATE
located in SYS$SYSDEVICE:[TCPIP$LD_BKR], then rename the file to
TCPIP$LBROKER.CONF.
After making changes to TCPIP$LBROKER.CONF, restart the load broker by
running TCPIP$CONFIG, or by using the shutdown and startup procedures.
The load broker configuration file can contain one or more DNS cluster
statements in the following format:
cluster "clustername.domain.com"
{
[dns-ttl nn;]
[dns-refresh nn;]
masters {ip_address};
[polling-interval nn;]
[max-members nn;]
members {ip_address};
failover {ip_address};
};
Table 6–1 describes the valid cluster statements.
Table 6–1 Valid Cluster Statements
Statement Description
members Specifies the IP address for each DNS cluster member.
failover Specifies the address of the host to use if all other members
are down.
masters Specifies the IP addresses of authoritative name servers.
dns-ttl Specifies the time to live for a given record. The value you
provide governs how long the record is to be cached by other
name servers. If some intermediate name servers cache A
resource records for a given DNS cluster name, they cache it
for the period specified by
dns-ttl for the resource record.
The default value is 45 seconds.
dns-refresh Specifies how often the DNS information for a given DNS
cluster name is refreshed. The default is 30 seconds. The
value of this field should be set relative to to the value of
polling-interval . The dns-refresh value should be
smaller than the
polling-interval value. It is unproductive
to refresh more often then you poll.
polling-interval Specifies the length of time between polls to cluster members.
The default is 30 seconds.
max-members Specifies the maximum number of IP addresses to be returned
to the name server in each dynamic update. For effective
load balancing, this number should be between one-third and
one-half the number of participating DNS cluster members.
The following sample is a configuration of the load broker that load balances the
DNS cluster named WWW.TCPIP.ERN.SEA.COM.
6–6 Using DNS to Balance Work Load