This parameter is only relevant if you are using Oracle Real Application Cluster (RAC).
The instances running in parallel to the dedicated database instance are defined by this parameter.
parallel_instances = <inst_descr>|(<inst_descr_list>)
Default value: none.
Possible value:
<inst_descr>: <ORACLE_SID>:<ORACLE_HOME>@<conn_str>
where:
<ORACLE_SID>: Oracle System ID of the parallel instance
<ORACLE_HOME>: ORACLE_HOME directory of the parallel instance
<conn_str>: Oracle connection string for connect to the parallel instance (for example, TNS alias in TSNAMES.ora)
parallel_instances = (RAC001:/oracle/RAC/112_64@RAC001, RAC002:/oracle/RAC/112_64@RAC002, RAC003:/oracle/RAC/112_64@RAC003
Specify all database instances in this parameter.