DNS issue not failover to secondary DNS

[billa07]

I have confiugured with 3 DNS server IP in Oracle EBS /DATABASE running OS HP -UNIX.

If first DNS server is not active then its not fail over to the secondary DNS, because of that oracle listener got time out and unable to acess the webservice. Kindly your help  to fix this issue

[Bill Hassell]

DNS is normally handled inside HP-UX. Do you know if Oracle EBS handles its own DNS resolution? Or did the EBS program just configure the /etc/resolv.conf file in HP-UX?

[billa07]

Just configure the  3 DNS IP on resolv.conf file for the server naming resolution..If one of the DNS IP fail then its took long time to handle the query to the second DNS IP . And because of that some oracle oracle listener got hung and clients are unable to communicate .

[Bill Hassell · Accepted solution]

The failover time for /etc/resolv.conf is 30 seconds for each DNS server. You have to configure Oracle to wait 100 seconds before giving up.

Better yet, don't use hostnames. IP addresses for database engines should never change so they can be hardcoded in the configs. No DNS timeout ever.

[Bill Hassell]

A more complete answer is that the DNS resolver can be configured for retry and timeout. These 2 values can be set in /etc/resolv.conf as follows:

retrans value_in_milliseconds
retry qty

For example, to have a system wait 2 seconds for a reply and retry 3 times after
a timeout:

retrans 2000
retry 3