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对rman命令report obsolete的一点说明

RMAN备份集数量超过备份保留策略后,report obsolete 一定会报其过期吗?测试设置了备份冗余策略为1,备份两次归档,发起report obsolete 命令希望能看到过期的归档备份集,但结果却未显示该备份集obsolete,看来有必要好好研究下,于是有下文。

一 先看看report obsolete命令的官方说明


Lists full backups, data file copies, and archived redo log files recorded in the 
RMAN repository that can be deleted because they are no longer needed  The command works 
in two steps:

 
For each data file that has been backed up, RMAN identifies the oldest full 
backup, level 0 backup, or image copy that is not obsolete under the 
retention policy. Any backup of the data file older than the one identified in 
this step is considered obsolete.

Any archived redo log files and level 1 incremental backups that are older 
than the oldest nonobsolete full backup are considered obsolete. These files 
are obsolete because no full or level 0 backup exists to which they can be 
applied. Incremental level 1 backups or archived redo log files are not 
considered obsolete if they can be applied to nonobsolete level 0 or full 
backups.

第一段:
report obsolete命令用于列出rman资料库中能够被删除的全备份、数据文件拷贝和归档日志记录。
report obsolete 命令有两个过程

第二段:
对数据文件备份的处理:对于每一个已经备份的数据文件,rman会在保留策略内标识出一个最老的的全数据备份或者0级别备份,如果其它任何数据文件备份比已标识的备份还老则再这一步直接认作obsolete

第三段
对归档日志文件或者增量备份处理:
首先应该有一个参照,这个参照就是保留策略内最老的非obsolete 全备份或者0级备份。
如果归档文件或者增量备份比标识的非obsolete且最老的full backup 还老,则视为obsolete。
如果归档文件或者增量备份能够被应用在一个非obsolete的全备份或者0级别备份,则归档及增量备份为非obsolete,反之则为obsolete。


二 验证

 

1 当前数据库备份保留策略配置如下
RMAN> show all;
using target database control file instead of recovery catalog
RMAN configuration parameters for database with db_unique_name CRM are:
CONFIGURE RETENTION POLICY TO REDUNDANCY 1;

2 当前数据库的obsolete备份集情况如下:
RMAN> report obsolete;

RMAN retention policy will be applied to the command
RMAN retention policy is set to redundancy 1
no obsolete backups found

3 备份数据库的所有归档两次
RMAN> run{ 
2> allocate channel c1 type disk; 
3> backup  archivelog all format ‘/backup/arch2_%T_%U’;
4> release channel c1;  
5> }

released channel: ORA_DISK_1
released channel: ORA_DISK_2
released channel: ORA_DISK_3
allocated channel: c1
channel c1: SID=131 device type=DISK

Starting backup at 2013-03-27 16:15:47
current log archived
channel c1: starting archived log backup set
channel c1: specifying archived log(s) in backup set
input archived log thread=1 sequence=124 RECID=843 STAMP=811181727
input archived log thread=1 sequence=125 RECID=844 STAMP=811181727
input archived log thread=1 sequence=126 RECID=845 STAMP=811181728
input archived log thread=1 sequence=127 RECID=846 STAMP=811181729
input archived log thread=1 sequence=128 RECID=847 STAMP=811181729
input archived log thread=1 sequence=129 RECID=848 STAMP=811181730
input archived log thread=1 sequence=130 RECID=849 STAMP=811181747
channel c1: starting piece 1 at 2013-03-27 16:15:48
channel c1: finished piece 1 at 2013-03-27 16:15:49
piece handle=/backup/arch2_20130327_0mo5j9lj_1_1 tag=TAG20130327T161547 comment=NONE
channel c1: backup set complete, elapsed time: 00:00:01
Finished backup at 2013-03-27 16:15:49

Starting Control File and SPFILE Autobackup at 2013-03-27 16:15:49
piece handle=/backup/c-3599153036-20130327-04 comment=NONE
Finished Control File and SPFILE Autobackup at 2013-03-27 16:15:50

released channel: c1

RMAN> run{ 
2> allocate channel c1 type disk; 
3> backup  archivelog all format ‘/backup/arch2_%T_%U’;
4> release channel c1;  
5> }

allocated channel: c1
channel c1: SID=131 device type=DISK

Starting backup at 2013-03-27 16:15:56
current log archived
channel c1: starting archived log backup set
channel c1: specifying archived log(s) in backup set
input archived log thread=1 sequence=124 RECID=843 STAMP=811181727
input archived log thread=1 sequence=125 RECID=844 STAMP=811181727
input archived log thread=1 sequence=126 RECID=845 STAMP=811181728
input archived log thread=1 sequence=127 RECID=846 STAMP=811181729
input archived log thread=1 sequence=128 RECID=847 STAMP=811181729
input archived log thread=1 sequence=129 RECID=848 STAMP=811181730
input archived log thread=1 sequence=130 RECID=849 STAMP=811181747
input archived log thread=1 sequence=131 RECID=850 STAMP=811181756
channel c1: starting piece 1 at 2013-03-27 16:15:56
channel c1: finished piece 1 at 2013-03-27 16:15:57
piece handle=/backup/arch2_20130327_0oo5j9ls_1_1 tag=TAG20130327T161556 comment=NONE
channel c1: backup set complete, elapsed time: 00:00:01
Finished backup at 2013-03-27 16:15:57

Starting Control File and SPFILE Autobackup at 2013-03-27 16:15:57
piece handle=/backup/c-3599153036-20130327-05 comment=NONE
Finished Control File and SPFILE Autobackup at 2013-03-27 16:15:58

released channel: c1

4 再次查看report obsolete的显示,发现无任何归档备份集obsolete情况。

注意:到此为止,数据库还未做过全备份,即缺乏比较的参照物“the oldest nonobsolete full backup”。

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           838    2013-03-27 16:09:54
  Backup Piece       847    2013-03-27 16:09:54 /backup/c-3599153036-20130327-03
Backup Set           840    2013-03-27 16:15:50
  Backup Piece       849    2013-03-27 16:15:50 /backup/c-3599153036-20130327-04
  
5 做一次数据库全备份(即让数据库产生一个“the oldest nonobsolete full backup”)


RMAN> run{ 
2> allocate channel c1 type disk; 
3> backup  database format ‘/backup/fulldb_%T_%U’;
4> release channel c1;  
5> }

allocated channel: c1
channel c1: SID=131 device type=DISK

Starting backup at 2013-03-27 16:16:58
channel c1: starting full datafile backup set
channel c1: specifying datafile(s) in backup set
input datafile file number=00004 name=/oracle/CRM/test2/USERS4.dbf
input datafile file number=00001 name=/oracle/CRM/test2/SYSTEM1.dbf
input datafile file number=00002 name=/oracle/CRM/test2/SYSAUX2.dbf
input datafile file number=00005 name=/oracle/CRM/test2/pos1.dbf
input datafile file number=00003 name=/oracle/CRM/test2/UNDOTBS33.dbf
input datafile file number=00006 name=/oracle/CRM/test2/ERP6.dbf
input datafile file number=00009 name=/oracle/CRM/test2/pos2.dbf
input datafile file number=00007 name=/oracle/CRM/test2/USER017.dbf
input datafile file number=00008 name=/oracle/CRM/test2/TEST8.dbf
channel c1: starting piece 1 at 2013-03-27 16:16:58
channel c1: finished piece 1 at 2013-03-27 16:19:43
piece handle=/backup/fulldb_20130327_0qo5j9nq_1_1 tag=TAG20130327T161658 comment=NONE
channel c1: backup set complete, elapsed time: 00:02:46
Finished backup at 2013-03-27 16:19:44

Starting Control File and SPFILE Autobackup at 2013-03-27 16:19:44
piece handle=/backup/c-3599153036-20130327-06 comment=NONE
Finished Control File and SPFILE Autobackup at 2013-03-27 16:19:47

released channel: c1

6 数据库的日志情况如下(可发现当前oracle最后一个归档seq号为131)


SQL> select group#,archived,sequence#,status from v$Log;

    GROUP# ARC  SEQUENCE# STATUS
———- — ———- —————-
         1 YES        129 INACTIVE
         2 YES        130 INACTIVE
         3 YES        131 INACTIVE
         4 NO         132 CURRENT

现在我们发起report obsolete命令,则系统内所有归档备份集和归档文件会和这个保留策略内”the oldest nonobsolete full backup“做比较 凡是无用的归档备份集和归档日志则在rman资料库内标记为obsolete。

 


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           837    2013-03-27 16:09:48
  Backup Piece       846    2013-03-27 16:09:48 /backup/fulldb1_20130327_0ho5j95g_1_1
Archive Log          844    2013-03-27 16:15:27 /oracle/archive/1_125_810495590.dbf
Backup Set           838    2013-03-27 16:09:54
  Backup Piece       847    2013-03-27 16:09:54 /backup/c-3599153036-20130327-03
Archive Log          843    2013-03-27 16:15:27 /oracle/archive/1_124_810495590.dbf
Archive Log          845    2013-03-27 16:15:28 /oracle/archive/1_126_810495590.dbf
Archive Log          846    2013-03-27 16:15:29 /oracle/archive/1_127_810495590.dbf
Archive Log          847    2013-03-27 16:15:29 /oracle/archive/1_128_810495590.dbf
Archive Log          848    2013-03-27 16:15:30 /oracle/archive/1_129_810495590.dbf
Archive Log          849    2013-03-27 16:15:47 /oracle/archive/1_130_810495590.dbf
Backup Set           839    2013-03-27 16:15:48
  Backup Piece       848    2013-03-27 16:15:48 /backup/arch2_20130327_0mo5j9lj_1_1
Backup Set           840    2013-03-27 16:15:50
  Backup Piece       849    2013-03-27 16:15:50 /backup/c-3599153036-20130327-04
Archive Log          850    2013-03-27 16:15:56 /oracle/archive/1_131_810495590.dbf
Backup Set           841    2013-03-27 16:15:56
  Backup Piece       850    2013-03-27 16:15:56 /backup/arch2_20130327_0oo5j9ls_1_1
Backup Set           842    2013-03-27 16:15:58
  Backup Piece       851    2013-03-27 16:15:58 /backup/c-3599153036-20130327-05

总结:
1 归档备份集如果obsolete,,则恢复数据库时该备份集所包含的归档无须被应用到保留策略内最旧非obsolete的一个全备份。

2 归档文件如果obsolete,则这些归档文件在数据库进行恢复时无须被应用到备份保留策略内最旧非obsolete的一个全库备份上。
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。

来自 “ ITPUB博客 ” ,链接:http://blog.itpub.net/27785870/viewspace-2106563/,如需转载,请注明出处,否则将追究法律责任。

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