在Oracle10g中，不管是否启用FLASHBACK，但只要设置了db_recovery_file_dest和db_recovery_file_dest_size参数值，那么RMAN默认会将备份集存储db_recovery_file_dest参数所指定的目录。

今天在测试机“玩”RMAN时，遇到如下错误：

RMAN> backup datafile 1;

Starting backup at 04-MAR-2011 21:28:24
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=132 devtype=DISK
channel ORA_DISK_1: starting full datafile backupset
channel ORA_DISK_1: specifying datafile(s) in backupset
input datafile fno=00001 name=+LIGLE_DATA1/ligle/datafile/system.261.742788005
channel ORA_DISK_1: starting piece 1 at 04-MAR-2011 21:28:25
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03009: failure of backup command on ORA_DISK_1 channel at 03/04/2011 21:28:51
ORA-19809: limit exceeded for recovery files
ORA-19804: cannot reclaim 52428800 bytes disk space from 314572800 limit

根据ORA-19809的提示信息，可知是由于flash_recovery_area空间不足所致。

SQL> select flashback_on from v$database;

FLASHBACK_ON
------------------
NO

SQL> select * from v$flash_recovery_area_usage;

FILE_TYPE PERCENT_SPACE_USED PERCENT_SPACE_RECLAIMABLE NUMBER_OF_FILES
------------ ------------------ ------------------------- ---------------
CONTROLFILE 0 0 0
ONLINELOG 0 0 0
ARCHIVELOG 0 0 0
BACKUPPIECE 58.36 6.22 3
IMAGECOPY 0 0 0
FLASHBACKLOG 0 0 0

6 rows selected.

SQL> show parameter db_recovery

NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
db_recovery_file_dest string /u01/flashback
db_recovery_file_dest_size big integer 300M

遇到这类问题有两种方法：

1、加大闪回恢复目录的大小（加大参数db_recovery_file_dest_size值）

SQL>ALTER SYSTEM SET db_recovery_file_dest_size=2G SCOPE=BOTH;

2、更改RMAN备份目录，在备份时指定备份目录。

RMAN> backup datafile 1 format '/u01/rmanbk/%U';