Undo_tablespace

 Hi,
I am in a process of db upgrade from 8.1.7.4 to 10.2.0.4 and hence I want to create undo tablespace.I found a metalink note but it is not suitable for my scenario:
Init.ora Parameters
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  1. UNDO_MANAGEMENT parameter must be set to AUTO.

  2. UNDO_TABLESPACE = <tablespace name> : This parameter allows the instance
     to use the specified UNDO TABLESPACE during instance startup, in case
     more than one undo tablespace exists.
 
     For eg:  UNDO_TABLESPACE = rbs
   
     This parameter need not be declared in init.ora at database creation time.
      

Creating an undo tablespace during database creation:
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In the CREATE DATABASE statement, use the UNDO TABLESPACE clause to specify the