玩过业务库的DBA应该面对一个问题，就是归档日志的删除和备份集的删除时间策略的问题？
RMAN>show all;
参数里面有个保留策略，默认下是重复多少次后就可以删除，小仙我一般设置成多少天后可以被删除，然实际上并非如此，实际上是可以被恢复到几天。目前设置的是3天，也就是可以保证可以恢复到3天以前。
expired 有中文意思过期，和 无效两个意思。
obsolete 表示 过时的，废弃的。
这两个词好像都是近义词啊！
真相是 obsolete 表示过期的 expired表示无效的。
先来看归档日志，来检查一下
RMAN> crosscheck archivelog all;
released channel: ORA_DISK_1
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=68 device type=DISK
validation succeeded for archived log
archived log file name=/u01/archive/1_24917_882200602.dbf RECID=66827 STAMP=950991475
validation succeeded for archived log
archived log file name=/u01/archive/1_24918_882200602.dbf RECID=66830 STAMP=950991527
validation succeeded for archived log
archived log file name=/u01/archive/1_24919_882200602.dbf RECID=66833 STAMP=950991529
validation succeeded for archived log
archived log file name=/u01/archive/1_24920_882200602.dbf RECID=66836 STAMP=951009052
validation succeeded for archived log
archived log file name=/u01/archive/1_24921_882200602.dbf RECID=66839 STAMP=951073772
validation succeeded for archived log
archived log file name=/u01/archive/1_24922_882200602.dbf RECID=66841 STAMP=951073774
validation succeeded for archived log
archived log file name=/u01/archive/1_24923_882200602.dbf RECID=66845 STAMP=951159044
validation succeeded for archived log
archived log file name=/u01/archive/1_24924_882200602.dbf RECID=66848 STAMP=951160178
validation succeeded for archived log
archived log file name=/u01/archive/1_24925_882200602.dbf RECID=66850 STAMP=951160179
validation succeeded for archived log
archived log file name=/u01/archive/1_24926_882200602.dbf RECID=66854 STAMP=951239328
validation succeeded for archived log
archived log file name=/u01/archive/1_24927_882200602.dbf RECID=66857 STAMP=951246587
validation succeeded for archived log
archived log file name=/u01/archive/1_24928_882200602.dbf RECID=66860 STAMP=951246588
validation succeeded for archived log
archived log file name=/u01/archive/1_24929_882200602.dbf RECID=66863 STAMP=951309750
validation succeeded for archived log
archived log file name=/u01/archive/1_24930_882200602.dbf RECID=66866 STAMP=951332969
validation succeeded for archived log
archived log file name=/u01/archive/1_24931_882200602.dbf RECID=66869 STAMP=951332970
validation succeeded for archived log
archived log file name=/u01/archive/1_24932_882200602.dbf RECID=66872 STAMP=951393093
validation succeeded for archived log
archived log file name=/u01/archive/1_24933_882200602.dbf RECID=66875 STAMP=951419421
validation succeeded for archived log
archived log file name=/u01/archive/1_24934_882200602.dbf RECID=66878 STAMP=951419422
validation succeeded for archived log
archived log file name=/u01/archive/1_24935_882200602.dbf RECID=66881 STAMP=951478734
validation succeeded for archived log
archived log file name=/u01/archive/1_24936_882200602.dbf RECID=66884 STAMP=951506898
validation succeeded for archived log
archived log file name=/u01/archive/1_24937_882200602.dbf RECID=66887 STAMP=951506900
validation succeeded for archived log
archived log file name=/u01/archive/1_24938_882200602.dbf RECID=66890 STAMP=951596363
validation succeeded for archived log
archived log file name=/u01/archive/1_24939_882200602.dbf RECID=66892 STAMP=951596364
Crosschecked 23 objects
检查了23个归档日志，并且都是OK的。我们在去磁盘上看看
[oracle@oraclemain archive]ll
total 7.7G
-rw-r----- 1 oracle oinstall 853M Aug 2 20:17 1_24917_882200602.dbf
-rw-r----- 1 oracle oinstall 755K Aug 2 20:18 1_24918_882200602.dbf
-rw-r----- 1 oracle oinstall 1.5K Aug 2 20:18 1_24919_882200602.dbf
-rw-r----- 1 oracle oinstall 141M Aug 3 01:10 1_24920_882200602.dbf
-rw-r----- 1 oracle oinstall 685M Aug 3 19:09 1_24921_882200602.dbf
-rw-r----- 1 oracle oinstall 30K Aug 3 19:09 1_24922_882200602.dbf
-rw-r----- 1 oracle oinstall 853M Aug 4 18:50 1_24923_882200602.dbf
-rw-r----- 1 oracle oinstall 9.8M Aug 4 19:09 1_24924_882200602.dbf
-rw-r----- 1 oracle oinstall 3.0K Aug 4 19:09 1_24925_882200602.dbf
-rw-r----- 1 oracle oinstall 853M Aug 5 17:08 1_24926_882200602.dbf
-rw-r----- 1 oracle oinstall 59M Aug 5 19:09 1_24927_882200602.dbf
-rw-r----- 1 oracle oinstall 1.5K Aug 5 19:09 1_24928_882200602.dbf
-rw-r----- 1 oracle oinstall 853M Aug 6 12:42 1_24929_882200602.dbf
-rw-r----- 1 oracle oinstall 244M Aug 6 19:09 1_24930_882200602.dbf
-rw-r----- 1 oracle oinstall 16K Aug 6 19:09 1_24931_882200602.dbf
-rw-r----- 1 oracle oinstall 853M Aug 7 11:51 1_24932_882200602.dbf
-rw-r----- 1 oracle oinstall 341M Aug 7 19:10 1_24933_882200602.dbf
-rw-r----- 1 oracle oinstall 2.0K Aug 7 19:10 1_24934_882200602.dbf
-rw-r----- 1 oracle oinstall 855M Aug 8 11:38 1_24935_882200602.dbf
-rw-r----- 1 oracle oinstall 443M Aug 8 19:28 1_24936_882200602.dbf
-rw-r----- 1 oracle oinstall 5.5K Aug 8 19:28 1_24937_882200602.dbf
-rw-r----- 1 oracle oinstall 818M Aug 9 20:19 1_24938_882200602.dbf
-rw-r----- 1 oracle oinstall 17K Aug 9 20:19 1_24939_882200602.dbf
从磁盘上看归档日志是对的上的。
我们手工删除第一个归档日志24917然后去检查下
[oracle@oraclemain archive]rm 1_24917_882200602.dbf
RMAN> crosscheck archivelog all;
released channel: ORA_DISK_1
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=68 device type=DISK
validation failed for archived log
archived log file name=/u01/archive/1_24917_882200602.dbf RECID=66827 STAMP=950991475
结果表示该归档日志无效了
列出无效的归档日志
RMAN> list expired archivelog all;
List of Archived Log Copies for database with db_unique_name ORCL_PD
=====================================================================
Key Thrd Seq S Low Time
66827 1 24917 X 01-AUG-17
Name: /u01/archive/1_24917_882200602.dbf删除无效的归档日志
RMAN> delete expired archivelog all;
released channel: ORA_DISK_1
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=68 device type=DISK
List of Archived Log Copies for database with db_unique_name ORCL_PD
=====================================================================
Key Thrd Seq S Low Time
66827 1 24917 X 01-AUG-17
Name: /u01/archive/1_24917_882200602.dbfDo you really want to delete the above objects (enter YES or NO)? YES
deleted archived log
archived log file name=/u01/archive/1_24917_882200602.dbf RECID=66827 STAMP=950991475
Deleted 1 EXPIRED objects
总结的说一下：备份信息保存在控制文件中或者是恢复目录中，所谓的备份信息就是上面的归档日志信息，备份集信息等。如果在OS操作系统上面手工删除了的话，那么控制文件它是不会自动感知的。需要交叉检查下，核对下！避免到时候恢复的时候使用错误的信息，导致无法恢复之类的。很显然上面的删除只是删除控制文件中的信息。
要是把控制文件的信息和磁盘的归档日志一起删除的呢？
我一般使用下面语句删除归档日志
DELETE archivelog until time 'sysdate-3'；
这条语句就是两者一起删除掉。
再看OBSOLETE；
RMAN> report obsolete;
RMAN retention policy will be applied to the command
RMAN retention policy is set to recovery window of 3 days
Report of obsolete backups and copies
Type Key Completion Time Filename/Handle
Backup Set 10250 07-AUG-17
Backup Piece 10250 07-AUG-17 /u01/backup/orcl_spfile_0csbb0j4_1_1_20170807
上面信息说明 该备份集已经过期了，超过了保留策略3天。可以被删除
delete obsolete;
就能把它删得比较干净
下面从OS看，为什么8月2日的备份集没有过期呢？
[oracle@oraclemain backup]ll
total 67G
-rw-r----- 1 oracle oinstall 12G Aug 2 19:31 orcl_datafile_level_0_uusatq1k_1_1_20170802
-rw-r----- 1 oracle oinstall 12G Aug 2 19:57 orcl_datafile_level_0_uvsatrsi_1_1_20170802
-rw-r----- 1 oracle oinstall 8.3G Aug 2 20:18 orcl_datafile_level_0_v0sattd5_1_1_20170802
-rw-r----- 1 oracle oinstall 279M Aug 2 20:19 orcl_archivelog_v2satul9_1_1_20170802
-rw-r----- 1 oracle oinstall 108M Aug 3 19:03 orcl_datafile_level_1_v6sb0edk_1_1_20170803
-rw-r----- 1 oracle oinstall 131M Aug 3 19:06 orcl_datafile_level_1_v7sb0ekc_1_1_20170803
-rw-r----- 1 oracle oinstall 127M Aug 3 19:09 orcl_datafile_level_1_v8sb0eq5_1_1_20170803
-rw-r----- 1 oracle oinstall 267M Aug 3 19:10 orcl_archivelog_vasb0evf_1_1_20170803
-rw-r----- 1 oracle oinstall 125M Aug 4 19:03 orcl_datafile_level_1_vesb32pk_1_1_20170804
-rw-r----- 1 oracle oinstall 132M Aug 4 19:06 orcl_datafile_level_1_vfsb330m_1_1_20170804
-rw-r----- 1 oracle oinstall 123M Aug 4 19:09 orcl_datafile_level_1_vgsb335s_1_1_20170804
-rw-r----- 1 oracle oinstall 287M Aug 4 19:10 orcl_archivelog_visb33bk_1_1_20170804
-rw-r----- 1 oracle oinstall 100M Aug 5 19:03 orcl_datafile_level_1_vmsb5n5j_1_1_20170805
-rw-r----- 1 oracle oinstall 114M Aug 5 19:06 orcl_datafile_level_1_vnsb5ncv_1_1_20170805
-rw-r----- 1 oracle oinstall 100M Aug 5 19:09 orcl_datafile_level_1_vosb5ni5_1_1_20170805
-rw-r----- 1 oracle oinstall 300M Aug 5 19:10 orcl_archivelog_vqsb5nnt_1_1_20170805
-rw-r----- 1 oracle oinstall 103M Aug 6 19:03 orcl_datafile_level_1_vusb8bhj_1_1_20170806
-rw-r----- 1 oracle oinstall 83M Aug 6 19:06 orcl_datafile_level_1_vvsb8bol_1_1_20170806
-rw-r----- 1 oracle oinstall 106M Aug 6 19:09 orcl_datafile_level_1_00sb8btg_1_1_20170806
-rw-r----- 1 oracle oinstall 355M Aug 6 19:10 orcl_archivelog_02sb8c3b_1_1_20170806
-rw-r----- 1 oracle oinstall 127M Aug 7 19:03 orcl_datafile_level_1_06sbavtl_1_1_20170807
-rw-r----- 1 oracle oinstall 196M Aug 7 19:06 orcl_datafile_level_1_07sbb051_1_1_20170807
-rw-r----- 1 oracle oinstall 132M Aug 7 19:10 orcl_datafile_level_1_08sbb0ag_1_1_20170807
-rw-r----- 1 oracle oinstall 390M Aug 7 19:11 orcl_archivelog_0asbb0gv_1_1_20170807
-rw-r----- 1 oracle oinstall 1.9M Aug 7 19:11 orcl_controlfile_0bsbb0j1_1_1_20170807
-rw-r----- 1 oracle oinstall 121M Aug 8 19:11 orcl_datafile_level_1_0esbdk9m_1_1_20170808
-rw-r----- 1 oracle oinstall 142M Aug 8 19:18 orcl_datafile_level_1_0fsbdkug_1_1_20170808
-rw-r----- 1 oracle oinstall 217M Aug 8 19:27 orcl_datafile_level_1_0gsbdlbq_1_1_20170808
-rw-r----- 1 oracle oinstall 408M Aug 8 19:29 orcl_archivelog_0isbdluk_1_1_20170808
-rw-r----- 1 oracle oinstall 1.9M Aug 8 19:29 orcl_controlfile_0jsbdm0n_1_1_20170808
-rw-r----- 1 oracle oinstall 96K Aug 8 19:29 orcl_spfile_0ksbdm0q_1_1_20170808
-rw-r----- 1 oracle oinstall 14G Aug 9 19:32 orcl_datafile_level_0_0msbg8lj_1_1_20170809
-rw-r----- 1 oracle oinstall 8.4G Aug 9 19:54 orcl_datafile_level_0_0nsbgaie_1_1_20170809
-rw-r----- 1 oracle oinstall 9.7G Aug 9 20:19 orcl_datafile_level_0_0osbgbs5_1_1_20170809
-rw-r----- 1 oracle oinstall 268M Aug 9 20:20 orcl_archivelog_0qsbgdac_1_1_20170809
-rw-r----- 1 oracle oinstall 1.9M Aug 9 20:20 orcl_controlfile_0rsbgdbr_1_1_20170809
-rw-r----- 1 oracle oinstall 96K Aug 9 20:20 orcl_spfile_0ssbgdbu_1_1_20170809
这个嘛 就是增量备份了 8月2日是增量备份0级别，不能把它给删了，昨天9号才开始新的增量0级备份。