BR0100E : Make sure full format of initSIDThread.ora for all instances exist and SPfile does not coexist in $ORACLE_HOME/dbs directory.
How to build full version of initSIDthread.ora
During enabling RAC for a single instance db, create a ora file which will have common init.ora parameters and create single initSIDthread.ora files having only the following parameters with reference to common init.ora file:
initSIDtherad2.ora
#Instance specific Parameters for RAC
instance_number = 002
thread = 002
instance_name = C17002
service_names = (C17,C17002)
undo_tablespace=PSAPUNDO2
ifile = /oracle/SID/920_64/dbs/icommon.ora
Create initSIDthread1.ora as well.
Then issue the following to create a single SPfile from these two combinations :
sqlplus> Create SPFILE from PFILE; ( do this by connecting to each DB instances this will create ingle initSIDtherad1 and 2.ora)
Then move SPfiles to a backup dir and you are ready to roll your backups, archives etc.