UNIX - Remove an ASM instance and its corresponding database(s) (Disk Storage)

This operation will DESTROY any databases that are currently running on the +ASM instance

1) Shutdown all databases that are running on the box using the +ASM instance for storage management 

2) Use emca -x <sid> to remove the Database Console for each instance

3) Clear the existing raw disks

      dd if=/dev/zero of=<raw device> bs=8192 count=1000

OR
     
      drop the raw partition

4) Drop the old parameter file (init<sid>.ora or spfile<sid>.ora)

       Default location: <ORACLE_HOME>/dbs

5) Delete / Remove any non ASM supporting directories

       BACKGROUND_DUMP_DEST
       USER_DUMP_DEST
       CORE_DUMP_DEST
       etc

6) Remove the ORATAB entry for the ASM instance

7) Remove the resource from cluster ready services (CRS)

     if RAC: srvctl remove asm -n nodename
     if Standalone: $ORACLE_HOME/bin/localconfing -delete

At this point ... if desired ... a new ASM instance should be able to be recreated (DBCA or manual) ... if necessary ... recreate the raw partitions