因手工删除归档日志，在使用RMAN进行归档日志备份的时候报如下错误：
RMAN> backup database plus archivelog delete input;

Starting backup at 08-FEB-09
current log archived
using target database controlfile instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=17 devtype=DISK
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of backup command at 02/08/2009 08:28:19
RMAN-06059: expected archived log not found, lost of archived log compromises recoverability
ORA-19625: error identifying file /u01/oracle/arch1_2.dbf
ORA-27037: unable to obtain file status
Linux Error: 2: No such file or directory
Additional information: 3

解决方法：
$ rman target / nocatalog
RMAN> crosscheck archivelog all;  

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What is your method of deleting your previous archivelogs? Is it OS command?
If OS command, your controlfile might not be updated so it treats that those archivelogs are still available in your disk. You should update your controlfile when deleting archivelogs using OS command.

RMAN> crosscheck archivelog all; // validate all archvelogs in your disk. If some are missing, it will treat it as expired.
RMAN> delete expired archivelog all; // it ill delete expired archivelog and updates your controlfile.