Interconnect setup in RAC



Last updated on November 23rd, 2015 at 03:42 pm

The interconnect is a very important part of the cluster environment it is on of the aorta’s of a cluster environment. The interconnect is used as physical layer between the cluster nodes to perform heartbeats as well as the cache fusion is using it. The interconnect must be a private connection. Cross over cable is not support.

In a day to day operation it is proven that when the interconnect is configured correctly the interconnect will not be the bottleneck in case of performance issues. In the rest of this article will be focus on the how to validate the interconnect is really used. An DBA must be able to validate the interconnect settings in case of performance problems. Out of scope is the physical attachment of the interconnect.

Although you should thread performance issues in a Cluster environment the way you would normally also do in no-cluster environments here some area’s you can focus on. Normally the average interconnect latency using gigabit must be < 5ms. Latency around 2ms are normal.

 

How to check Interconnect setup  in RAC

10g and 11g
set linesize 120
col name for a22
col ip_address for a15

select inst_id,name,ip_address,is_public from gv$configured_interconnects order by 1,2;

INST_ID NAME IP_ADDRESS IS_PUBLIC
———- ———————- ————— ———
1 en11 145.72.220.10 YES
1 en12 145.72.220.83 NO
2 en11 145.72.220.20 YES
2 en12 145.72.220.84 NO

Used interfaces for the interconnect ?
In 1.1.1 the interfaces available are listed, but which interface is used for the cache fusion part ? And make sure the interconnect is using the correct interface ?
set linesize 120
col name for a22
col ip_address for a15
select inst_id,name,ip_address,is_public from gv$cluster_interconnects order by 1,2;

INST_ID NAME IP_ADDRESS IS_PUBLIC
———- ———————- ————— ———
1 en12 145.72.220.83 NO
2 en12 145.72.220.84 NO

9i,10g and 11gOradebug
Before the above queries where available (10g and 11g) you needed to use oradebug to validate if the correct interface was used. This was the way to validate the interconnect usage in Oracle 9i, bust still possible in 10g and 11g as well.

SQL> connect / as sysdba
SQL> alter session set tracefile_identifier=oradebug_interc
SQL> oradebug setmypid
SQL> oradebug ipc
SQL> exit

Now if you open the tracefile, in the bdump location, you can find the IP address used for the interconnect. Here is the result of the above oradebug ipc command.


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