背景
今天尝试备份完整数据库时，我遇到了错误，提示 RMAN 无法访问其中一个数据文件。我发现数据文件没有任何用处，因此我已将数据文件脱机删除，但 RMAN 仍然不允许我备份数据库。当您确定数据文件没有任何用处时，这是解决此类问题的解决方案之一。
解决方案
RMAN> backup database;
Starting backup at 09-DEC-12
using channel ORA_DISK_1
could not read file header for datafile 9 error reason 4
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of backup command at 12/09/2012 14:28:13
RMAN-06056: could not access datafile 9
RMAN> backup database skip inaccessible;
Starting backup at 09-DEC-12
using channel ORA_DISK_1
could not access datafile 9
skipping inaccessible file 9
RMAN-06060: WARNING: skipping datafile compromises tablespace RMAN recoverability
RMAN-06060: WARNING: skipping datafile compromises tablespace RMAN recoverability
channel ORA_DISK_1: starting full datafile backupset
channel ORA_DISK_1: specifying datafile(s) in backupset
input datafile fno=00001 name=/u01/app/oracle/oradata/orcl/system01.dbf
input datafile fno=00003 name=/u01/app/oracle/oradata/orcl/sysaux01.dbf
input datafile fno=00006 name=/u01/app/oracle/aliflaila
input datafile fno=00005 name=/u01/app/oracle/oradata/orcl/example01.dbf
input datafile fno=00008 name=/u01/app/oracle/oradata/orcl/undotbs007.dbf
input datafile fno=00002 name=/u01/app/oracle/oradata/orcl/undotbs01.dbf
input datafile fno=00004 name=/u01/app/oracle/oradata/orcl/users01.dbf
input datafile fno=00007 name=/u01/app/oracle/oradata/orcl/users02.dbf
channel ORA_DISK_1: starting piece 1 at 09-DEC-12