IBM PowerHA(HACMP) shutdowns oracle 11.2 because of IPv6 and DNS is not accessable


Just a quick post with some additions to situation covered in

Investigation of the 11g Oracle*Net connection delay when DNS server is unreachable.

Just a short recap:

  • customer experienced long timeout(slow connection) doing tnsping to 11.2 database running on AIX when DNS server was unreachable;


TNS Ping Utility for IBM/AIX RISC System/6000: Version – Production

Attempting to contact (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = dns-hostname)(PORT = 1521))   (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = XXX)))

OK (150010 msec)

  • issue was because of IPv6 support was included in Oracle 11g and even if connection hostname was resolved by /etc/hosts to IPv4 client tried to resolve it to IPv6 address too.
  • issue was fixed by replacing local, bind by local4, bind4  in the /etc/netsvc.conf.

So why I’m doing this recap ?

It’s because of mentioned problem was only a part of issue faced during IBM PowerHA(HACMP) cluster with oracle resources testing. Continue reading


Investigation of the 11g Oracle*Net connection delay when DNS server is unreachable

Oleksandr Denysenko:

“I’d like to introduce new Contributor to this Blog – Robert Oliynichenko.

Hi will make post on topics that are related to main direction of this Blog.

So, here we have The First Post about Slow 11.2 SQL*Net connections on AIX

Problem description:

Oracle 11g utilities like tnsping, lsnrctl or sqlplus on AIX 6.1 hanged for about 2,5 minutes (150 seconds) before connection with alias to any destination when DNS server was unreachable. In the same conditions (host and configuration) 10g utilities connected without delay. Oracle*Net was configured for local naming method only – NAMES.DIRECTORY_PATH=(tnsnames) in the both 10g and 11g Oracle Home. The tnsnames.ora files where identical in the 10g and 11g Oracle Home. The aliases in the tnsnames.ora used host names instead of IP addresses in the connection descriptions; if a host name was substituted by IP address the delay disappeared for this alias. Nevertheless all the host names from tnsnames where described in the /etc/hosts and resolution order was hosts = local, bind in the netsvc.conf (analog of  the nsswitch.conf in other UNIXs). This configuration should guarantee local name resolution when DNS server was unreachable. What is the root reason of this delay in 11g Oracle*Net ? Continue reading