今天有朋友对于crosscheck和obsolete理解的不太清楚，网上查找了一些资料，也发现很多错误，其中典型的理解就是:crosscheck 可以检测/删除违背(obsolete)备份策略的备份集
--登录rman
[oracle@node1 ~]$ $ORACLE_HOME/bin/rman target /
Recovery Manager: Release 10.2.0.5.0 - Production on Tue Nov 8 13:39:17 2011
Copyright (c) 1982, 2007, Oracle. All rights reserved.
connected to target database: ECP (DBID=1669273445)
RMAN> show all;
using target database control file instead of recovery catalog
RMAN configuration parameters are:
CONFIGURE RETENTION POLICY TO REDUNDANCY 1;
CONFIGURE BACKUP OPTIMIZATION OFF; # default
CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default
CONFIGURE CONTROLFILE AUTOBACKUP OFF; # default
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '%F'; # default
CONFIGURE DEVICE TYPE DISK PARALLELISM 2 BACKUP TYPE TO COMPRESSED BACKUPSET;
CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE CHANNEL DEVICE TYPE DISK MAXPIECESIZE 2048 M;
CONFIGURE MAXSETSIZE TO UNLIMITED; # default
CONFIGURE ENCRYPTION FOR DATABASE OFF; # default
CONFIGURE ENCRYPTION ALGORITHM 'AES128'; # default
CONFIGURE ARCHIVELOG DELETION POLICY TO NONE; # default
CONFIGURE SNAPSHOT CONTROLFILE NAME TO '/opt/oracle/product/10.2.0/db_1/dbs/snapcf_ecp.f'; # default
--发现配置的策略是保留1份
--全库备份
RMAN> list backup summary;
--当前数据库无备份集备份
RMAN> backup database format '/opt/backup/ecp_full_%U';
Starting backup at 2011-11-08 13:22:06
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=536 devtype=DISK
allocated channel: ORA_DISK_2
channel ORA_DISK_2: sid=534 devtype=DISK
channel ORA_DISK_1: starting compressed full datafile backupset
channel ORA_DISK_1: specifying datafile(s) in backupset
input datafile fno=00004 name=/opt/oracle/oradata/ecp/users01.dbf
input datafile fno=00003 name=/opt/oracle/oradata/ecp/sysaux01.dbf
input datafile fno=00008 name=/opt/oracle/oradata/ecp/TS_Public_1.003.dbf
input datafile fno=00009 name=/opt/oracle/oradata/ecp/TS_Index_Base.001.dbf
input datafile fno=00010 name=/opt/oracle/oradata/ecp/TS_Index_Base.002.dbf
input datafile fno=00011 name=/opt/oracle/oradata/ecp/TS_Index_Base.003.dbf
channel ORA_DISK_1: starting piece 1 at 2011-11-08 13:22:07
channel ORA_DISK_2: starting compressed full datafile backupset
channel ORA_DISK_2: specifying datafile(s) in backupset
input datafile fno=00002 name=/opt/oracle/oradata/ecp/undotbs01.dbf
input datafile fno=00001 name=/opt/oracle/oradata/ecp/system01.dbf
input datafile fno=00012 name=/opt/oracle/oradata/ecp/OGG.001.dbf
input datafile fno=00005 name=/opt/oracle/oradata/ecp/example01.dbf
input datafile fno=00006 name=/opt/oracle/oradata/ecp/TS_Public_1.001.dbf
input datafile fno=00007 name=/opt/oracle/oradata/ecp/TS_Public_1.002.dbf
channel ORA_DISK_2: starting piece 1 at 2011-11-08 13:22:07
channel ORA_DISK_1: finished piece 1 at 2011-11-08 13:22:22
piece handle=/opt/backup/ecp_full_11mr52bv_1_1 tag=TAG20111108T132207 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:15
channel ORA_DISK_1: starting compressed full datafile backupset
channel ORA_DISK_1: specifying datafile(s) in backupset
including current control file in backupset
channel ORA_DISK_1: starting piece 1 at 2011-11-08 13:22:23
channel ORA_DISK_1: finished piece 1 at 2011-11-08 13:22:24
piece handle=/opt/backup/ecp_full_13mr52ce_1_1 tag=TAG20111108T132207 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:02
channel ORA_DISK_1: starting compressed full datafile backupset
channel ORA_DISK_1: specifying datafile(s) in backupset
including current SPFILE in backupset
channel ORA_DISK_1: starting piece 1 at 2011-11-08 13:22:25
channel ORA_DISK_1: finished piece 1 at 2011-11-08 13:22:26
piece handle=/opt/backup/ecp_full_14mr52cg_1_1 tag=TAG20111108T132207 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:02
channel ORA_DISK_2: finished piece 1 at 2011-11-08 13:22:41
piece handle=/opt/backup/ecp_full_12mr52bv_1_1 tag=TAG20111108T132207 comment=NONE
channel ORA_DISK_2: backup set complete, elapsed time: 00:00:34
Finished backup at 2011-11-08 13:22:41
--备份sysdata01.dbf文件
RMAN> backup datafile 1 format '/opt/backup/ecp_system_%U';
Starting backup at 2011-11-08 13:23:44
using channel ORA_DISK_1
using channel ORA_DISK_2
channel ORA_DISK_1: starting compressed full datafile backupset
channel ORA_DISK_1: specifying datafile(s) in backupset
input datafile fno=00001 name=/opt/oracle/oradata/ecp/system01.dbf
channel ORA_DISK_1: starting piece 1 at 2011-11-08 13:23:45
channel ORA_DISK_2: starting compressed full datafile backupset
channel ORA_DISK_2: specifying datafile(s) in backupset
including current control file in backupset
channel ORA_DISK_2: starting piece 1 at 2011-11-08 13:23:45
channel ORA_DISK_2: finished piece 1 at 2011-11-08 13:23:46
piece handle=/opt/backup/ecp_system_16mr52f1_1_1 tag=TAG20111108T132344 comment=NONE
channel ORA_DISK_2: backup set complete, elapsed time: 00:00:01
channel ORA_DISK_2: starting compressed full datafile backupset
channel ORA_DISK_2: specifying datafile(s) in backupset
including current SPFILE in backupset
channel ORA_DISK_2: starting piece 1 at 2011-11-08 13:23:47
channel ORA_DISK_2: finished piece 1 at 2011-11-08 13:23:48
piece handle=/opt/backup/ecp_system_17mr52f2_1_1 tag=TAG20111108T132344 comment=NONE
channel ORA_DISK_2: backup set complete, elapsed time: 00:00:02
channel ORA_DISK_1: finished piece 1 at 2011-11-08 13:24:13
piece handle=/opt/backup/ecp_system_15mr52f1_1_1 tag=TAG20111108T132344 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:28
Finished backup at 2011-11-08 13:24:13
--注：所有备份system空间，都是会自动备份spfile和控制文件
RMAN> list backup summary;
List of Backups
===============
Key TY LV S Device Type Completion Time #Pieces #Copies Compressed Tag
------- -- -- - ----------- ------------------- ------- ------- ---------- ---
28 B F A DISK 2011-11-08 13:22:19 1 1 YES TAG20111108T132207
29 B F A DISK 2011-11-08 13:22:23 1 1 YES TAG20111108T132207
30 B F A DISK 2011-11-08 13:22:25 1 1 YES TAG20111108T132207
31 B F A DISK 2011-11-08 13:22:35 1 1 YES TAG20111108T132207
32 B F A DISK 2011-11-08 13:23:45 1 1 YES TAG20111108T132344
33 B F A DISK 2011-11-08 13:23:47 1 1 YES TAG20111108T132344
34 B F A DISK 2011-11-08 13:24:03 1 1 YES TAG20111108T132344
--查看所有备份集情况
RMAN> crosscheck backup;
using channel ORA_DISK_1
using channel ORA_DISK_2
crosschecked backup piece: found to be 'AVAILABLE'
backup piece handle=/opt/backup/ecp_full_11mr52bv_1_1 recid=28 stamp=766675327
crosschecked backup piece: found to be 'AVAILABLE'
backup piece handle=/opt/backup/ecp_full_13mr52ce_1_1 recid=29 stamp=766675343
crosschecked backup piece: found to be 'AVAILABLE'
backup piece handle=/opt/backup/ecp_full_14mr52cg_1_1 recid=30 stamp=766675345
crosschecked backup piece: found to be 'AVAILABLE'
backup piece handle=/opt/backup/ecp_full_12mr52bv_1_1 recid=31 stamp=766675327
crosschecked backup piece: found to be 'AVAILABLE'
backup piece handle=/opt/backup/ecp_system_16mr52f1_1_1 recid=32 stamp=766675425
crosschecked backup piece: found to be 'AVAILABLE'
backup piece handle=/opt/backup/ecp_system_17mr52f2_1_1 recid=33 stamp=766675427
crosschecked backup piece: found to be 'AVAILABLE'
backup piece handle=/opt/backup/ecp_system_15mr52f1_1_1 recid=34 stamp=766675425
--查看全部有效
RMAN> report obsolete;
RMAN retention policy will be applied to the command
RMAN retention policy is set to redundancy 1
Report of obsolete backups and copies
Type Key Completion Time Filename/Handle
-------------------- ------ ------------------ --------------------
Backup Set 29 2011-11-08 13:22:23
Backup Piece 29 2011-11-08 13:22:23 /opt/backup/ecp_full_13mr52ce_1_1
Backup Set 30 2011-11-08 13:22:25
Backup Piece 30 2011-11-08 13:22:25 /opt/backup/ecp_full_14mr52cg_1_1
--因为system01.dbf备份了两次，所以违背了备份策略
drwxr-xr-x 2 root root 4096 07-12 15:54 vmdir
[root@node1 opt]# cd /opt/backup/
[root@node1 backup]# ll
总计 265356
-rw-r----- 1 oracle oinstall 47497216 11-08 13:22 ecp_full_11mr52bv_1_1
-rw-r----- 1 oracle oinstall 129433600 11-08 13:22 ecp_full_12mr52bv_1_1
-rw-r----- 1 oracle oinstall 1130496 11-08 13:22 ecp_full_13mr52ce_1_1
-rw-r----- 1 oracle oinstall 98304 11-08 13:22 ecp_full_14mr52cg_1_1
-rw-r----- 1 oracle oinstall 92012544 11-08 13:24 ecp_system_15mr52f1_1_1
-rw-r----- 1 oracle oinstall 1130496 11-08 13:23 ecp_system_16mr52f1_1_1
-rw-r----- 1 oracle oinstall 98304 11-08 13:23 ecp_system_17mr52f2_1_1
[root@node1 backup]# mv ecp_system_15mr52f1_1_1 ecp_system_15mr52f1_1_1_bak
[root@node1 backup]# ll
总计 265356
-rw-r----- 1 oracle oinstall 47497216 11-08 13:22 ecp_full_11mr52bv_1_1
-rw-r----- 1 oracle oinstall 129433600 11-08 13:22 ecp_full_12mr52bv_1_1
-rw-r----- 1 oracle oinstall 1130496 11-08 13:22 ecp_full_13mr52ce_1_1
-rw-r----- 1 oracle oinstall 98304 11-08 13:22 ecp_full_14mr52cg_1_1
-rw-r----- 1 oracle oinstall 92012544 11-08 13:24 ecp_system_15mr52f1_1_1_bak
-rw-r----- 1 oracle oinstall 1130496 11-08 13:23 ecp_system_16mr52f1_1_1
-rw-r----- 1 oracle oinstall 98304 11-08 13:23 ecp_system_17mr52f2_1_1
--对备份集中的其中一个文件重命名
RMAN> crosscheck backup;
using channel ORA_DISK_1
using channel ORA_DISK_2
crosschecked backup piece: found to be 'AVAILABLE'
backup piece handle=/opt/backup/ecp_full_11mr52bv_1_1 recid=28 stamp=766675327
crosschecked backup piece: found to be 'AVAILABLE'
backup piece handle=/opt/backup/ecp_full_13mr52ce_1_1 recid=29 stamp=766675343
crosschecked backup piece: found to be 'AVAILABLE'
backup piece handle=/opt/backup/ecp_full_14mr52cg_1_1 recid=30 stamp=766675345
crosschecked backup piece: found to be 'AVAILABLE'
backup piece handle=/opt/backup/ecp_full_12mr52bv_1_1 recid=31 stamp=766675327
crosschecked backup piece: found to be 'AVAILABLE'
backup piece handle=/opt/backup/ecp_system_16mr52f1_1_1 recid=32 stamp=766675425
crosschecked backup piece: found to be 'AVAILABLE'
backup piece handle=/opt/backup/ecp_system_17mr52f2_1_1 recid=33 stamp=766675427
Crosschecked 6 objects
crosschecked backup piece: found to be 'EXPIRED'
backup piece handle=/opt/backup/ecp_system_15mr52f1_1_1 recid=34 stamp=766675425
Crosschecked 1 objects
--发现一个无效的备份集
RMAN> list backup summary;
List of Backups
===============
Key TY LV S Device Type Completion Time #Pieces #Copies Compressed Tag
------- -- -- - ----------- ------------------- ------- ------- ---------- ---
28 B F A DISK 2011-11-08 13:22:19 1 1 YES TAG20111108T132207
29 B F A DISK 2011-11-08 13:22:23 1 1 YES TAG20111108T132207
30 B F A DISK 2011-11-08 13:22:25 1 1 YES TAG20111108T132207
31 B F A DISK 2011-11-08 13:22:35 1 1 YES TAG20111108T132207
32 B F A DISK 2011-11-08 13:23:45 1 1 YES TAG20111108T132344
33 B F A DISK 2011-11-08 13:23:47 1 1 YES TAG20111108T132344
34 B F X DISK 2011-11-08 13:24:03 1 1 YES TAG20111108T132344
--也标志为无效'X'
RMAN> report obsolete;
RMAN retention policy will be applied to the command
RMAN retention policy is set to redundancy 1
Report of obsolete backups and copies
Type Key Completion Time Filename/Handle
-------------------- ------ ------------------ --------------------
Backup Set 29 2011-11-08 13:22:23
Backup Piece 29 2011-11-08 13:22:23 /opt/backup/ecp_full_13mr52ce_1_1
Backup Set 30 2011-11-08 13:22:25
Backup Piece 30 2011-11-08 13:22:25 /opt/backup/ecp_full_14mr52cg_1_1
--策略还是显示这两个备份集违背规则
RMAN> DELETE NOPROMPT OBSOLETE;
RMAN retention policy will be applied to the command
RMAN retention policy is set to redundancy 1
using channel ORA_DISK_1
using channel ORA_DISK_2
Deleting the following obsolete backups and copies:
Type Key Completion Time Filename/Handle
-------------------- ------ ------------------ --------------------
Backup Set 29 2011-11-08 13:22:23
Backup Piece 29 2011-11-08 13:22:23 /opt/backup/ecp_full_13mr52ce_1_1
Backup Set 30 2011-11-08 13:22:25
Backup Piece 30 2011-11-08 13:22:25 /opt/backup/ecp_full_14mr52cg_1_1
deleted backup piece
backup piece handle=/opt/backup/ecp_full_13mr52ce_1_1 recid=29 stamp=766675343
deleted backup piece
backup piece handle=/opt/backup/ecp_full_14mr52cg_1_1 recid=30 stamp=766675345
Deleted 2 objects
RMAN> report obsolete;
RMAN retention policy will be applied to the command
RMAN retention policy is set to redundancy 1
no obsolete backups found
--删除违法策略的备份集
RMAN> delete NOPROMPT expired backup;
using channel ORA_DISK_1
using channel ORA_DISK_2
List of Backup Pieces
BP Key BS Key Pc# Cp# Status Device Type Piece Name
------- ------- --- --- ----------- ----------- ----------
34 34 1 1 EXPIRED DISK /opt/backup/ecp_system_15mr52f1_1_1
deleted backup piece
backup piece handle=/opt/backup/ecp_system_15mr52f1_1_1 recid=34 stamp=766675425
Deleted 1 EXPIRED objects
RMAN> crosscheck backup;
using channel ORA_DISK_1
using channel ORA_DISK_2
crosschecked backup piece: found to be 'AVAILABLE'
backup piece handle=/opt/backup/ecp_full_11mr52bv_1_1 recid=28 stamp=766675327
crosschecked backup piece: found to be 'AVAILABLE'
backup piece handle=/opt/backup/ecp_full_12mr52bv_1_1 recid=31 stamp=766675327
crosschecked backup piece: found to be 'AVAILABLE'
backup piece handle=/opt/backup/ecp_system_16mr52f1_1_1 recid=32 stamp=766675425
crosschecked backup piece: found to be 'AVAILABLE'
backup piece handle=/opt/backup/ecp_system_17mr52f2_1_1 recid=33 stamp=766675427
Crosschecked 4 objects
--删除无效的备份集
通过实验说明：crosscheck只能够检测备份集是否有效(最常见的情况就是物理上是否还存在),并且可以用它来删除失效(expired)的备份集，而不是用来删除违背备份策略(obsolete)的备份集，如果要删除违背备份策略(废弃)的备份集，需要使用obsolete操作。出现这个问题的主要原因应该是expired和obsolete翻译成中文的时候理解的出入导致。
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