$ sqlplus /nolog
SQL*Plus: Release 11.2.0.4.0 Production on Fri Apr 25 20:20:46 2014
Copyright (c) 1982, 2013, Oracle. All rights reserved.
SQL> conn /as sysdba;
Connected.
SQL>
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup nomount;
ORACLE instance started.
Total System Global Area 3273641984 bytes
Fixed Size 2257680 bytes
Variable Size 1879051504 bytes
Database Buffers 1375731712 bytes
Redo Buffers 16601088 bytes
SQL>
SQL> show parameter db_recovery_file_dest_size;
NAME TYPE
------------------------------------ ----------------------
VALUE
------------------------------
db_recovery_file_dest_size big integer
3882M
SQL>
SQL> alter system set db_recovery_file_dest_size=4882M scope=spfile;
System altered.
SQL> shutdown
ORA-01507: database not mounted
ORACLE instance shut down.
SQL> startup
ORACLE instance started.
Total System Global Area 3273641984 bytes
Fixed Size 2257680 bytes
Variable Size 1879051504 bytes
Database Buffers 1375731712 bytes
Redo Buffers 16601088 bytes
Database mounted.
Database opened.
SQL> quit