今天我在自己的测试数据库上用RMAN作数据文件的备份，出现了rman-03002错误。如下:

RMAN> BACKUP FORMAT 'C:\BACKUP\RMAN2\TEST.BAK'
2> TABLESPACE USERS plus archivelog;

Starting backup at 03-7月 -08
using channel ORA_DISK_1
channel ORA_DISK_1: starting archive log backupset
channel ORA_DISK_1: specifying archive log(s) in backup set
input archive log thread=1 sequence=1 recid=11 stamp=658787803
input archive log thread=1 sequence=12 recid=13 stamp=659046512
input archive log thread=1 sequence=13 recid=15 stamp=659052082
input archive log thread=1 sequence=14 recid=17 stamp=659053712
input archive log thread=1 sequence=15 recid=19 stamp=659066437
input archive log thread=1 sequence=16 recid=21 stamp=659089902
input archive log thread=1 sequence=17 recid=23 stamp=659110213
input archive log thread=1 sequence=18 recid=25 stamp=659110399
input archive log thread=1 sequence=19 recid=27 stamp=659110545
input archive log thread=1 sequence=20 recid=29 stamp=659110665
channel ORA_DISK_1: starting piece 1 at 03-7月 -08
channel ORA_DISK_1: finished piece 1 at 03-7月 -08
piece handle=C:\BACKUP\RMAN2\TEST.BAK comment=NONE
channel ORA_DISK_1: starting piece 2 at 03-7月 -08
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of backup plus archivelog command at 07/03/2008 14:32:29
ORA-19504: failed to create file "C:\BACKUP\RMAN2\TEST.BAK"
ORA-27038: created file already exists
OSD-04010: option specified, file already exists

我想明明文件不存在呀,为什么说文件已经存在了呢？

上google查了一下RMAN-03003错误，大概知道有可能跟文件大小有关系，突然想到自己在前面已经设置了备份片的大小为15M(RMAN>configure channel device type disk

                     2 MAXPIECESIZE 15M);

于是我试着把前面的设置取消掉：rman>configure channel device type disk clear;

然后又备份刚才的数据文件与归档日志：

RMAN> BACKUP FORMAT 'C:\BACKUP\RMAN2\TEST.BAK'
2> TABLESPACE USERS plus archivelog;

哈哈，成功备份！