SQL> select N.Name, /* rollback segment name */
2 S.OptSize /* rollback segment OPTIMAL size */
3 from V$ROLLNAME N, V$ROLLSTAT S
4 where N.USN=S.USN;
NAME OPTSIZE
------------------------------ ----------
SYSTEM
_SYSSMU1$
_SYSSMU2$
_SYSSMU3$
_SYSSMU4$
_SYSSMU5$
_SYSSMU6$
_SYSSMU7$
_SYSSMU8$
_SYSSMU9$
_SYSSMU10$
SQL>