I build a new OH - no RAC option, and restarted the database under that OH.
oracle(TXDEV)@oracnp01 ~/product/10.2.0/db_2 > sqlplus / as sysdba
SQL*Plus: Release 10.2.0.3.0 - Production on Mon Apr 7 14:05:02 2008
Copyright (c) 1982, 2006, Oracle. All Rights Reserved.
Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.3.0 - 64bit Production
With the Partitioning option
SQL> select * from v$cluster_interconnects;
no rows selected
So it does look as though it was starting up the DB under an OH with
the RAC option that was the culprit.
