Oracle 11g中对于归档日志的删除，除了遵循RMAN保留策略外，也可以通过RMAN来配置归档日志的删除策略，也就是归档日志何时可以被删除。归档日志删除策略适用于所有归档位置(使用快速闪回区FRA/不使用FRA)。本文主要描述归档日志删除策略并给出了具体的演示。
1、关于归档日志删除策略
也就是哪些归档日志符合删除策略能够被删除，如前所述，归档位置适用于所有归档位置(使用快速闪回区FRA/不使用FRA)
当启用该策略后，如归档日志存在于FRA中，则Oracle会尽可能根据保留他们，一旦FRA空间告急，则Oracle会根据归档日志删除策略自动删除
对于不在FRA中的归档日志，需要手动使用delete obsolete或delete archivelog方式来删除日志
无论归档日志存在于FRA内或外，都可以通过BACKUP ... DELETE INPUT or DELETE ARCHIVELOG方式来删除
该策略不适用于使用LogMiner方式从主数据库传送到逻辑standby生成的外部归档日志文件，因为这些日志文件不能够在逻辑standy上备份或恢复
2、配置归档日志删除策略
使用下面的方式来配置归档日志删除策略
configure archivelog deletion policy to backed up 2 times to sbt;
configure archivelog deletion policy to backed up 1 times to device type disk;
configure archivelog deletion policy to applied on standby;
configure archivelog deletion policy to shipped on standby;
configure archivelog deletion policy clear;
对于Oracle 10g没有该特性，但有一个类似的用于配置归档日志被备份次数，如下；
configure archivelog backup copies for device type disk to ${archiveretention};
3、禁用归档日志删除策略
缺省情况下，该策略被设置为none。也就是说根据RMAN备份保留策略，对于FRA中的归档日志，被备份过一次(到磁盘或磁带)即符合条件被删除
如果Oracle不再需要当前的归档日志用于保证数据库时点恢复或数据库闪回，则RMAN备份保留策略认为当前日志为obsolete
在SYSDATE-'DB_FLASHBACK_RETENTION_TARGET'之后创建的归档日志是需要被保留的
4、启用归档日志删除策略
一旦启用该策略，则指定的归档日志被备份数量达到设定值后，这些归档日志能够被删除
BACKUP ARCHIVELOG 会在未超出指定备份数的情况下(比如设置为2)备份归档日志到指定位置，如超出2次，则RMAN会跳过这些备份过2次的归档日志
对于上述的情形，可以为BACKUP ARCHIVELOG适用force选项来强制备份归档日志
如果启用该策略且配置为APPLIED ON STANDBY子句，则所有强制standby位置被apply后，这些归档日志会被RMAN删除
如果启用该策略且配置为SHIPPED ON STANDBY子句，则所有强制standby位置被成功传送后，这些归档日志会被RMAN删除
5、演示归档日志删除策略
[oracle@linux1 ~]$ rman target /
Recovery Manager: Release 11.2.0.1.0 - Production on Tue Nov 12 15:10:17 2013
--查看当前数据库保留策略
RMAN> show retention policy;
RMAN configuration parameters for database with db_unique_name USBO are:
CONFIGURE RETENTION POLICY TO REDUNDANCY 1; # default
--查看当前数据库保归档日志留策略
RMAN> show archivelog deletion policy;
RMAN configuration parameters for database with db_unique_name USBO are:
CONFIGURE ARCHIVELOG DELETION POLICY TO NONE; # default
--查看过时的备份
RMAN> report obsolete;
RMAN retention policy will be applied to the command
RMAN retention policy is set to redundancy 1
no obsolete backups found
--列出copy副本
RMAN> list copy;
specification does not match any datafile copy in the repository
specification does not match any control file copy in the repository
List of Archived Log Copies for database with db_unique_name USBO
=====================================================================
Key Thrd Seq S Low Time
------- ---- ------- - -------------------
124 1 121 A 2013/11/12 15:34:15
Name: /u03/database/usbo/fr_area/USBO/archivelog/2013_11_12/o1_mf_1_121_983pm3gp_.arc --当前的归档日志
--修改当前的归档日志保留策略为2个备份副本
RMAN> configure archivelog deletion policy to backed up 2 times to device type disk;
new RMAN configuration parameters:
CONFIGURE ARCHIVELOG DELETION POLICY TO BACKED UP 2 TIMES TO DISK;
new RMAN configuration parameters are successfully stored
--备份归档日志，并删除已经备份的归档日志
RMAN> backup archivelog all delete input;
Starting backup at 2013/11/12 15:37:25
current log archived
using channel ORA_DISK_1
channel ORA_DISK_1: starting archived log backup set
channel ORA_DISK_1: specifying archived log(s) in backup set
input archived log thread=1 sequence=121 RECID=124 STAMP=831310563
input archived log thread=1 sequence=122 RECID=125 STAMP=831310645
channel ORA_DISK_1: starting piece 1 at 2013/11/12 15:37:26
channel ORA_DISK_1: finished piece 1 at 2013/11/12 15:37:27
piece handle=/u03/database/usbo/fr_area/USBO/backupset/2013_11_12/o1_mf_annnn_TAG20131112T153726_983pop3p_.bkp
tag=TAG20131112T153726 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
channel ORA_DISK_1: deleting archived log(s)
RMAN-08138: WARNING: archived log not deleted - must create more backups --->出现警告提示，日志当前不能被删除，更多的备份需要创建
archived log file name=/u03/database/usbo/fr_area/USBO/archivelog/2013_11_12/o1_mf_1_121_983pm3gp_.arc thread=1 sequence=121
RMAN-08138: WARNING: archived log not deleted - must create more backups
archived log file name=/u03/database/usbo/fr_area/USBO/archivelog/2013_11_12/o1_mf_1_122_983pooxb_.arc thread=1 sequence=122
Finished backup at 2013/11/12 15:37:27
--从os层面查看归档日志，当前已备份的两个归档日志没有删除
sys@USBO> ho ls -hltr /u03/database/usbo/fr_area/USBO/archivelog/2013_11_12/*
-rw-r----- 1 oracle asmadmin 3.0K Nov 12 15:36 /u03/database/usbo/fr_area/USBO/archivelog/2013_11_12/o1_mf_1_121_983pm3gp_.arc
-rw-r----- 1 oracle asmadmin 4.5K Nov 12 15:37 /u03/database/usbo/fr_area/USBO/archivelog/2013_11_12/o1_mf_1_122_983pooxb_.arc
--从视图查询也可以获得其状态
sys@USBO> select name,status from v$archived_log where STATUS='A';
NAME STA
-------------------------------------------------------------------------------- ---
/u03/database/usbo/fr_area/USBO/archivelog/2013_11_12/o1_mf_1_121_983pm3gp_.arc A
/u03/database/usbo/fr_area/USBO/archivelog/2013_11_12/o1_mf_1_122_983pooxb_.arc A
--第二次备份归档日志
-- Author : Leshami
-- Blog : http://blog.csdn.net/leshami
RMAN> backup archivelog all delete input tag=arc_2nd;
Starting backup at 2013/11/12 15:41:58
current log archived
using channel ORA_DISK_1
channel ORA_DISK_1: starting archived log backup set
channel ORA_DISK_1: specifying archived log(s) in backup set
input archived log thread=1 sequence=121 RECID=124 STAMP=831310563 --sequence 121与122依旧被备份
input archived log thread=1 sequence=122 RECID=125 STAMP=831310645
input archived log thread=1 sequence=123 RECID=126 STAMP=831310918
channel ORA_DISK_1: starting piece 1 at 2013/11/12 15:41:58
channel ORA_DISK_1: finished piece 1 at 2013/11/12 15:41:59
piece handle=/u03/database/usbo/fr_area/USBO/backupset/2013_11_12/o1_mf_annnn_ARC_2ND_983py6mv_.bkp tag=ARC_2ND comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
channel ORA_DISK_1: deleting archived log(s) --sequence 121与122被删除
archived log file name=/u03/database/usbo/fr_area/USBO/archivelog/2013_11_12/o1_mf_1_121_983pm3gp_.arc RECID=124 STAMP=831310563
archived log file name=/u03/database/usbo/fr_area/USBO/archivelog/2013_11_12/o1_mf_1_122_983pooxb_.arc RECID=125 STAMP=831310645
RMAN-08138: WARNING: archived log not deleted - must create more backups --->出现警告提示，日志123不能被删除，更多的备份需要创建
archived log file name=/u03/database/usbo/fr_area/USBO/archivelog/2013_11_12/o1_mf_1_123_983py6gh_.arc thread=1 sequence=123
--再次查看，只有sequence 123存在，121与122已经被删除
RMAN> list copy;
specification does not match any datafile copy in the repository
specification does not match any control file copy in the repository
List of Archived Log Copies for database with db_unique_name USBO
=====================================================================
Key Thrd Seq S Low Time
------- ---- ------- - -------------------
126 1 123 A 2013/11/12 15:37:25
Name: /u03/database/usbo/fr_area/USBO/archivelog/2013_11_12/o1_mf_1_123_983py6gh_.arc
Finished backup at 2013/11/12 15:41:59
--配置新的归档日志删除策略
RMAN> configure archivelog deletion policy to backed up 1 times to device type disk;
old RMAN configuration parameters:
CONFIGURE ARCHIVELOG DELETION POLICY TO BACKED UP 2 TIMES TO DISK;
new RMAN configuration parameters:
CONFIGURE ARCHIVELOG DELETION POLICY TO BACKED UP 1 TIMES TO DISK;
new RMAN configuration parameters are successfully stored
--第三次备份归档日志
RMAN> backup archivelog all tag=arc_3rd;
Starting backup at 2013/11/12 15:44:11
current log archived
using channel ORA_DISK_1 --下面是skip的提示信息，因为根据新的策略，sequence 123已经被备份过一次了
skipping archived log file /u03/database/usbo/fr_area/USBO/archivelog/2013_11_12/o1_mf_1_123_983py6gh_.arc; already backed up 1 time(s)
channel ORA_DISK_1: starting archived log backup set
channel ORA_DISK_1: specifying archived log(s) in backup set
input archived log thread=1 sequence=124 RECID=127 STAMP=831311051
channel ORA_DISK_1: starting piece 1 at 2013/11/12 15:44:12
channel ORA_DISK_1: finished piece 1 at 2013/11/12 15:44:13
piece handle=/u03/database/usbo/fr_area/USBO/backupset/2013_11_12/o1_mf_annnn_ARC_3RD_983q2d34_.bkp tag=ARC_3RD comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
Finished backup at 2013/11/12 15:44:13
--清除策略
RMAN> configure archivelog deletion policy clear;
old RMAN configuration parameters:
CONFIGURE ARCHIVELOG DELETION POLICY TO BACKED UP 1 TIMES TO DISK;
RMAN configuration parameters are successfully reset to default value
--列出所有归档日志的备份信息
RMAN> list backup of archivelog all;
List of Backup Sets
===================
BS Key Size Device Type Elapsed Time Completion Time
------- ---------- ----------- ------------ -------------------
24 8.00K DISK 00:00:00 2013/11/12 15:37:26
BP Key: 24 Status: AVAILABLE Compressed: NO Tag: TAG20131112T153726
Piece Name: /u03/database/usbo/fr_area/USBO/backupset/2013_11_12/o1_mf_annnn_TAG20131112T153726_983pop3p_.bkp
List of Archived Logs in backup set 24
Thrd Seq Low SCN Low Time Next SCN Next Time
---- ------- ---------- ------------------- ---------- ---------
1 121 3090437 2013/11/12 15:34:15 3090507 2013/11/12 15:36:03
1 122 3090507 2013/11/12 15:36:03 3090591 2013/11/12 15:37:25
BS Key Size Device Type Elapsed Time Completion Time
------- ---------- ----------- ------------ -------------------
25 37.50K DISK 00:00:00 2013/11/12 15:41:58
BP Key: 25 Status: AVAILABLE Compressed: NO Tag: ARC_2ND
Piece Name: /u03/database/usbo/fr_area/USBO/backupset/2013_11_12/o1_mf_annnn_ARC_2ND_983py6mv_.bkp
List of Archived Logs in backup set 25
Thrd Seq Low SCN Low Time Next SCN Next Time
---- ------- ---------- ------------------- ---------- ---------
1 121 3090437 2013/11/12 15:34:15 3090507 2013/11/12 15:36:03
1 122 3090507 2013/11/12 15:36:03 3090591 2013/11/12 15:37:25
1 123 3090591 2013/11/12 15:37:25 3090746 2013/11/12 15:41:58
BS Key Size Device Type Elapsed Time Completion Time
------- ---------- ----------- ------------ -------------------
26 2.50K DISK 00:00:00 2013/11/12 15:44:12
BP Key: 26 Status: AVAILABLE Compressed: NO Tag: ARC_3RD
Piece Name: /u03/database/usbo/fr_area/USBO/backupset/2013_11_12/o1_mf_annnn_ARC_3RD_983q2d34_.bkp
List of Archived Logs in backup set 26
Thrd Seq Low SCN Low Time Next SCN Next Time
---- ------- ---------- ------------------- ---------- ---------
1 124 3090746 2013/11/12 15:41:58 3090839 2013/11/12 15:44:11
相关参考
RMAN 配置保留策略
Oracle 闪回区(Oracle Flash recovery area)
Oracle 快照控制文件(snapshot control file)
基于RMAN的异机数据库克隆(rman duplicate)
基于RMAN从活动数据库异机克隆(rman duplicate from active DB)
RMAN duplicate from active 时遭遇 ORA-17627 ORA-12154
Oracle 基于备份控制文件的恢复(unsing backup controlfile)
