Parameter CLUSTER_INTERCONNECTS - RAC

 Parameter CLUSTER_INTERCONNECTS - RAC

CLUSTER_INTERCONNECTS

CLUSTER_INTERCONNECTS can be used in Oracle Real Application Clusters environments to indicate cluster interconnects available for use for the database traffic.

Property	Description
Parameter type	String
Syntax	CLUSTER_INTERCONNECTS = ifn [: ifn ] ...
Default value	There is no default value.
Modifiable	No
Modifiable in a PDB	No
Range of values	One or more IP addresses, separated by colons
Basic	No

Use this parameter to override the default interconnect configured for the database traffic, which is stored in the cluster registry. This procedure also may be useful with Data Warehouse systems that have reduced availability requirements and high interconnect bandwidth demands.

CLUSTER_INTERCONNECTS specifically overrides the following:

• Network classifications stored by oifcfg in the OCR.

• The default interconnect chosen by Oracle.

If you want to load-balance the interconnect, then Oracle recommends that you use link-bonding at the operating system level, even if you have two databases on the same server, so that multiple interconnects use the same address. Note that multiple private addresses provide load balancing, but do not provide failover unless bonded. If you specify multiple addresses in init.ora using CLUSTER_INTERCONNECTS, instead of bonding multiple addresses at the operating system level, then typically availability is reduced, because each network interface card failure will take down that instance.

Refer to your vendor documentation for information about bonding interfaces. Some vendor bonding architectures may require the use of this parameter.

If you have multiple database instances on Oracle Real Application Clusters nodes and want to use a specific interface for each instance, then you can set the CLUSTER_INTERCONNECTS initialization parameter to the IP address for each database instance. For example:

hr1.init.ora.cluster_interconnects="192.0.2.111"
oltp3.init.ora.cluster_interconnects="192.0.2.112"

If the Oracle RAC interconnect is configured to run on a different interface than the Oracle Clusterware interconnect, then this configuration can cause reduced availability, as failovers or instance evictions can be delayed if the Oracle RAC interconnect fails while the Oracle Clusterware NIC remains up.

Set Cluster Interconnects in Oracle RAC

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To set the cluster interconnects in the RAC

• Delete any references of the cluster_interconnect on the interfaces.

Before

host1$ oifcfg getif
ce0  192.168.1.0  global  cluster_interconnect
ce4  10.0.102.0   global  public

Delete cluster interconnects using oifcfg.

host1$ oifcfg delif -global ce0

After

host1$ oifcfg getif
ce4  10.0.102.0   global  public

• The cluster_interconnects initialization parameter must be manually overrode its the default value from the OCR.

Before

SQL> select * from gv$cluster_interconnects;

   INST_ID NAME            IP_ADDRESS       IS_ SOURCE
---------- --------------- ---------------- --- -------------------------------
         1 ce0             192.168.1.50     NO  Oracle Cluster Repository
         2 ce0             192.168.1.51     NO  Oracle Cluster Repository

Update the initialization parameters in both ASM and RAC database.

alter system set cluster_interconnects =  '192.168.1.50' scope=spfile sid='RAC1' ; 
alter system set cluster_interconnects =  '192.168.1.51' scope=spfile sid='RAC2' ;  

After

SQL> select * from gv$cluster_interconnects;

   INST_ID NAME            IP_ADDRESS       IS_ SOURCE
---------- --------------- ---------------- --- -------------------------------
         1 ce0             192.168.1.50     NO  cluster_interconnects parameter     <== Source is changed
         2 ce0             192.168.1.51     NO  cluster_interconnects parameter     <== Source is changed