Rollback segment question (need help)

I have defined a non-system tablespace. When I tried to defined a rollback segment for it, I encountered a problem. The exact process is as follows:

1. First I use CREATE TABLESPACE to define a tablespace named mc_space.

      CREATE TABLESPACE mc_space
           DATAFILE 'path/dbfitd.dbf' SIZE 80M REUSE
           DEFAULT STORAGE (INITIAL 5M NEXT 50K
                       MINEXTENTS 1 MAXEXTENTS 100
		       PCTINCREASE 0)

2. Then I tried to define a rollback segment named roll_mc for it

     CREATE ROLLBACK SEGMENT roll_mc
	  TABLESPACE mc_space
	  STORAGE (INITIAL 50000 NEXT 50000 MAXEXTENTS 100);

3. Meanwhile I changed the init.ora file under $ORACLE_HOME/dbs, and

   shutdown the database and start it up. It kept telling me the error    "ORA-01552: cannot use system rollback segment for non-system    tablespace 'MC_SPACE' ".

I think I followed the step the manual tells me, but it still does not work. Does any of you have any idea what went wrong?

Any suggestion is welcome.

Thanks in advance.

• Fang

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Fang Feng                           "Time will erase everything"    
Texas A&M University                "Who knows what will happen