rman备份archivelog时出现以下错误：
RMAN> backup archivelog all delete input;
Starting backup at 14-APR-14
current log archived
using channel ORA_DISK_1
using channel ORA_DISK_2
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of backup command at 04/14/2014 18:40:23
RMAN-06059: expected archived log not found, loss of archived log compromises recoverability
ORA-19625: error identifying file /home/Oracle/PROD/1_2_844469007.dbf
ORA-27037: unable to obtain file status
Linux Error: 2: No such file or directory
Additional information: 3
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网上查了出错原因是由于操作系统下删除了这个归档日志，这个日志还没备份过，rman去备份的时候，找不到这个归档就出错了。可使用change archivelog all crosscheck命令来解决此问题，如下：
RMAN> change archivelog all crosscheck;
released channel: ORA_DISK_1
released channel: ORA_DISK_2
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=43 device type=DISK
allocated channel: ORA_DISK_2
channel ORA_DISK_2: SID=45 device type=DISK
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_16_827176743.dbf RECID=1 STAMP=844399662
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_17_827176743.dbf RECID=2 STAMP=844460245
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_18_827176743.dbf RECID=3 STAMP=844461320
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_19_827176743.dbf RECID=4 STAMP=844461426
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_20_827176743.dbf RECID=5 STAMP=844461580
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_21_827176743.dbf RECID=6 STAMP=844461592
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_22_827176743.dbf RECID=7 STAMP=844461696
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_23_827176743.dbf RECID=8 STAMP=844462037
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_24_827176743.dbf RECID=9 STAMP=844462165
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_25_827176743.dbf RECID=10 STAMP=844462279
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_26_827176743.dbf RECID=11 STAMP=844462409
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_27_827176743.dbf RECID=12 STAMP=844465108
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_28_827176743.dbf RECID=13 STAMP=844469010
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_1_844532679.dbf RECID=16 STAMP=844533450
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_2_844532679.dbf RECID=19 STAMP=844537684
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_2_844532679.dbf RECID=17 STAMP=844533553
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_3_844532679.dbf RECID=20 STAMP=844537685
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_4_844532679.dbf RECID=18 STAMP=844537684
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_1_844537684.dbf RECID=23 STAMP=844605032
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_1_844537684.dbf RECID=21 STAMP=844575254
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_2_844537684.dbf RECID=24 STAMP=844605033
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_2_844537684.dbf RECID=22 STAMP=844581004
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_3_844537684.dbf RECID=25 STAMP=844605034
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_1_844469007.dbf RECID=14 STAMP=844530587
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_1_844605031.dbf RECID=26 STAMP=844670045
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_2_844605031.dbf RECID=27 STAMP=844797748
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_3_844605031.dbf RECID=28 STAMP=844841532
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_4_844605031.dbf RECID=29 STAMP=844847317
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_5_844605031.dbf RECID=30 STAMP=844855807
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_6_844605031.dbf RECID=31 STAMP=844855838
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_7_844605031.dbf RECID=32 STAMP=844886422
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_8_844605031.dbf RECID=33 STAMP=844886590
validation succeeded for archived log
archived log file name=/home/oracle/PROD/1_9_844605031.dbf RECID=34 STAMP=844886622
Crosschecked 33 objects
validation failed for archived log
archived log file name=/home/oracle/PROD/1_2_844469007.dbf RECID=15 STAMP=844530793
Crosschecked 1 objects
--再次执行archivelog的rman备份就成功了，如下：
RMAN> backup archivelog all delete input;
Starting backup at 14-APR-14
current log archived
using channel ORA_DISK_1
using channel ORA_DISK_2
channel ORA_DISK_1: starting compressed archived log backup set
channel ORA_DISK_1: specifying archived log(s) in backup set
input archived log thread=1 sequence=16 RECID=1 STAMP=844399662
input archived log thread=1 sequence=17 RECID=2 STAMP=844460245
input archived log thread=1 sequence=18 RECID=3 STAMP=844461320
channel ORA_DISK_1: starting piece 1 at 14-APR-14
channel ORA_DISK_2: starting compressed archived log backup set
channel ORA_DISK_2: specifying archived log(s) in backup set
input archived log thread=1 sequence=1 RECID=16 STAMP=844533450
channel ORA_DISK_2: starting piece 1 at 14-APR-14
channel ORA_DISK_2: finished piece 1 at 14-APR-14
piece handle=/home/oracle/backup/PROD_20140414_1bp5ntq0_1_1.bak tag=TAG20140414T190432 comment=NONE
channel ORA_DISK_2: backup set complete, elapsed time: 00:00:02
channel ORA_DISK_2: deleting archived log(s)
archived log file name=/home/oracle/PROD/1_1_844532679.dbf RECID=16 STAMP=844533450
channel ORA_DISK_2: starting compressed archived log backup set
channel ORA_DISK_2: specifying archived log(s) in backup set
input archived log thread=1 sequence=19 RECID=4 STAMP=844461426
input archived log thread=1 sequence=20 RECID=5 STAMP=844461580
input archived log thread=1 sequence=21 RECID=6 STAMP=844461592
input archived log thread=1 sequence=22 RECID=7 STAMP=844461696
input archived log thread=1 sequence=23 RECID=8 STAMP=844462037
input archived log thread=1 sequence=24 RECID=9 STAMP=844462165
input archived log thread=1 sequence=25 RECID=10 STAMP=844462279
channel ORA_DISK_2: starting piece 1 at 14-APR-14
channel ORA_DISK_1: finished piece 1 at 14-APR-14
piece handle=/home/oracle/backup/PROD_20140414_1ap5ntq0_1_1.bak tag=TAG20140414T190432 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:03
channel ORA_DISK_1: deleting archived log(s)