通过RMAN设置standby接收日志后主库归档日志才可删除

谁践踏了优雅 2022-10-15 12:55 2阅读 0赞

因为[Oracle archivelog][]会不断生产，一般会设置[定期清理archivelog][Oracle archivelog]的排程，类似下面。

但[DG环境][Oracle archivelog]中因为某些原因导致主库事务没有即使传到standby，而这时如果主库的archivelog也被清理掉了，主备库就产生了日志GAP

export ORACLE\_SID=abc  
export ORACLE\_HOME=/u01/product/oracle/  
export PATH= O R A C L E H O M E / b i n : ORACLE\_HOME/bin: ORACLEHOME/bin:PATH  
export NLS\_LANG=AMERICAN\_AMERICA.AL32UTF8  
rman target / <<EOF  
run  
\{  
crosscheck archivelog all;  
DELETE NOPROMPT ARCHIVELOG until time ‘sysdate-7’;  
\}  
exit;  
EOF

如何能够确保standby日志接收到了，主库archivelog才会被删除呢？

11G 后提供了RMAN的archivelog删除策略

CONFIGURE ARCHIVELOG DELETION POLICY TO APPLIED ON STANDBY;

注：这里是说archivelog在standby目录中接收生产了，并不是被实际应用了。

因为这样说？一种情况standby正常开启，但MPR不开启应用redo，其实standby也能接收主库传递过来的archivelog但并没有被应用，这时主库的archivelog是可以被清理的

默认 CONFIGURE ARCHIVELOG DELETION POLICY TO APPLIED ON NONE;

SHOW ALL 命令能看到

实验

1.关闭standby DB，模拟standby无法接受archivelog

1.  主库rman中配置

CONFIGURE ARCHIVELOG DELETION POLICY TO APPLIED ON STANDBY;

1.  主库切换生成新log，模拟gap

SQL> alter system switch logfile;

SQL> /

4.因为standby未接收到archivelog，对主库备份archivelog同时加了DELETE INPUT清理归档报错RMAM-08120

RMAN> backup format ‘/data/exp/arch\_%T\_%s\_%U’ ARCHIVELOG ALL DELETE INPUT;  
Starting backup at 13-MAY-20  
current log archived  
using target database control file instead of recovery catalog  
allocated channel: ORA\_DISK\_1  
channel ORA\_DISK\_1: SID=9 device type=DISK  
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=12585 RECID=25142 STAMP=1040319318  
input archived log thread=1 sequence=12586 RECID=25144 STAMP=1040319532  
input archived log thread=1 sequence=12587 RECID=25146 STAMP=1040319628  
input archived log thread=1 sequence=12588 RECID=25147 STAMP=1040320146  
channel ORA\_DISK\_1: starting piece 1 at 13-MAY-20  
channel ORA\_DISK\_1: finished piece 1 at 13-MAY-20  
piece handle=/data/exp/arch\_20200513\_10\_0av041ki\_1\_1 tag=TAG20200513T174906 comment=NONE  
channel ORA\_DISK\_1: backup set complete, elapsed time: 00:00:01  
channel ORA\_DISK\_1: deleting archived log(s)  
archived log file name=/data/epodb/arch/1\_12585\_893259821.arc RECID=25142 STAMP=1040319318  
archived log file name=/data/epodb/arch/1\_12586\_893259821.arc RECID=25144 STAMP=1040319532  
RMAN-08120: WARNING: archived log not deleted, not yet applied by standby  
archived log file name=/data/epodb/arch/1\_12587\_893259821.arc thread=1 sequence=12587  
RMAN-08120: WARNING: archived log not deleted, not yet applied by standby  
archived log file name=/data/epodb/arch/1\_12588\_893259821.arc thread=1 sequence=12588  
Finished backup at 13-MAY-20

5.因为standby未接收到archivelog，对主库delete archivelog报错RMAM-08120

RMAN> delete archivelog until time ‘sysdate’ ;  
released channel: ORA\_DISK\_1  
allocated channel: ORA\_DISK\_1  
channel ORA\_DISK\_1: SID=9 device type=DISK  
RMAN-08120: WARNING: archived log not deleted, not yet applied by standby  
archived log file name=/data/epodb/arch/1\_12587\_893259821.arc thread=1 sequence=12587  
RMAN-08120: WARNING: archived log not deleted, not yet applied by standby  
archived log file name=/data/epodb/arch/1\_12588\_893259821.arc thread=1 sequence=12588  
注：如果带上FORCE参数可以忽略 RMAM-08120直接删除archivelog， delete FORCE archivelog until time ‘sysdate’ ;

完整实例：[http://github.crmeb.net/u/defu][Oracle archivelog]

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[Oracle archivelog]: http://github.crmeb.net/u/defu
[http_ym.baisou.ltd_post_610.html]: http://ym.baisou.ltd/post/610.html