先摘录一段对CROSSCHECK的描述
当archivelog或是backup被手工删除后，需要运行crosscheck.该命令确保recovery catalog或是控制文件中记录的数据与硬盘上的文件一致。
对于找不到的文件，CROSSCHECK会把它的状态标为EXPIRED.然后，你运行DELETE EXPIRED命令就可以把rman repository中的相关记录和硬盘上的文件删除。
如果有些文件被错误地标为EXPIRED,那么在确认文件存在时，再次运行CROSSCHECK BACKUP可以将这些文件重置为AVAILABLE状态。
也就是说，对于硬盘上已经不存在的文件，用DELETE EXPIRED在RMAN中删除相关记录。对于已经超过retention policy的备份，用DELETE OBSOLETE从硬盘和磁带设备上删除,并从RMAN中把记录删除。
在执行完
Crosscheck backup;
Crossscheck backuppiece;
Crosscheck archivelog all;
Delete obsolete;报RMAN-06091: no channel allocated for maintenance (of an appropriate type)
研究了一下，之前的备份一部分是直接备份在硬盘上,另一部分是通过DP备份在磁带上的。出现这样的错误是因为有磁带上的数据，但是未申请磁带类型的channel造成的。
RMAN> allocate channel for maintenance type disk;
allocated channel: ORA_MAINT_DISK_6
channel ORA_MAINT_DISK_6: sid=137 devtype=DISK
RMAN> delete expired archivelog all;
specification does not match any archive log in the recovery catalog
这个应该是正常的，没有发现expired log.
RMAN> delete obsolete;
RMAN retention policy will be applied to the command
RMAN retention policy is set to redundancy 1
Deleting the following obsolete backups and copies:
Type Key Completion Time Filename/Handle
-------------------- ------ ------------------ --------------------
Backup Set 2499 2011-11-24 11:39:28
Backup Piece 2511 2011-11-24 11:39:28 swt-oracle-full<gz_7:768051562:1>.dbf
…
Backup Set 2564 2011-11-26 21:18:57
Backup Piece 2567 2011-11-26 21:18:57 /backup/arc0dmsld1e
…
Backup Set 2950 2011-12-14 14:45:40
Backup Piece 2955 2011-12-14 14:45:40 /u01/oracle/flash_recovery_area/GZ/backupset/2011_12_14/o1_mf_annnn_TAG20111214T144526_7gjkjly0_.bkp
…
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of delete command at 12/15/2011 17:05:42
RMAN-06091: no channel allocated for maintenance (of an appropriate type)
这里出错了
解决的办法是分别删除硬盘上与磁带上的过期备份数据。
RMAN>delete obsolete device type disk;
删除硬盘上的过期备份
RMAN retention policy will be applied to the command
RMAN retention policy is set to redundancy 1
Deleting the following obsolete backups and copies:
Type Key Completion Time Filename/Handle
-------------------- ------ ------------------ --------------------
Backup Set 2509 2011-11-24 14:28:32
Backup Piece 2521 2011-11-24 14:28:32 /backup/sp
Backup Set 2564 2011-11-26 21:18:57
Backup Piece 2567 2011-11-26 21:18:57 /backup/arc0dmsld1e
Backup Set 2565 2011-11-26 21:19:20
Backup Piece 2568 2011-11-26 21:19:20 /backup/arc0emsld29
Control File Copy 2709 2011-11-26 21:42:33 /var/opt/omni/tmp/ctrl_gz.dbf
Backup Set 2885 2011-11-27 20:44:15
Backup Piece 2888 2011-11-27 20:44:15 /backup/db_full_31.1
Control File Copy 2898 2011-11-27 20:43:57 /backup/bj.ctl
Backup Set 2886 2011-11-27 20:44:21
Backup Piece 2889 2011-11-27 20:44:21 /backup/db_full_32.1
Backup Set 2950 2011-12-14 14:45:40
Backup Piece 2955 2011-12-14 14:45:40 /u01/oracle/flash_recovery_area/GZ/backupset/2011_12_14/o1_mf_annnn_TAG20111214T144526_7gjkjly0_.bkp
Backup Set 2951 2011-12-14 14:45:46
…
Do you really want to delete the above objects (enter YES or NO)? YES
deleted backup piece
backup piece handle=/backup/db_full_31.1 recid=31 stamp=768343384
deleted control file copy
control file copy filename=/backup/bj.ctl recid=4 stamp=768343437
deleted backup piece
backup piece handle=/backup/db_full_32.1 recid=32 stamp=768343461
deleted backup piece
backup piece handle=/u01/oracle/flash_recovery_area/GZ/backupset/2011_12_14/o1_mf_annnn_TAG20111214T144526_7gjkjly0_.bkp recid=38 stamp=769877137
deleted backup piece
…
Deleted 17 objects
deleted backup piece
backup piece handle=/backup/sp recid=11 stamp=768061712
deleted backup piece
backup piece handle=/backup/arc0dmsld1e recid=13 stamp=768259119
deleted backup piece
backup piece handle=/backup/arc0emsld29 recid=14 stamp=768259146
Deleted 3 objects
这回成功了
RMAN> allocate channel for maintenance device type 'sbt_tape' PARMS 'ENV=(OB2BARTYPE=Oracle8,OB2APPNAME=gz,OB2BARLIST=swt-oracle-full)';
这里PARMS后面的参数与备份时RMAN脚本中的参数相同
allocated channel: ORA_MAINT_SBT_TAPE_7
channel ORA_MAINT_SBT_TAPE_7: sid=136 devtype=SBT_TAPE
channel ORA_MAINT_SBT_TAPE_7: Data Protector A.06.11/243
RMAN> delete obsolete;
RMAN retention policy will be applied to the command
RMAN retention policy is set to redundancy 1
Deleting the following obsolete backups and copies:
Type Key Completion Time Filename/Handle
-------------------- ------ ------------------ --------------------
Backup Set 2499 2011-11-24 11:39:28
Backup Piece 2511 2011-11-24 11:39:28 swt-oracle-full<gz_7:768051562:1>.dbf
…
Do you really want to delete the above objects (enter YES or NO)? yes
deleted backup piece
backup piece handle=swt-oracle-full<gz_7:768051562:1>.dbf recid=1 stamp=768051562
…
Deleted 26 objects
这样就成功了