DG丢失归档，使用增量备份恢复一例，这里有一点要注意，因为使用的是standby controlfile，所以所有log文件（包括standby_log）的

发生了这种错误，主库丢失了归档，而备库无法同步日志

Media RecoveryWaiting for thread 1 sequence 70

Fetching gapsequence in thread 1, gap sequence 70-72

Completed: ALTERDATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT FROM SESSION

Wed Mar 07 18:26:312012

FAL[client]: Failedto request gap sequence

GAP - thread 1 sequence 70-72

DBID 3857759336 branch 768793323

FAL[client]: Alldefined FAL servers have been attempted.

-------------------------------------------------------------

Check that theCONTROL_FILE_RECORD_KEEP_TIME initialization

parameter is definedto a value that is sufficiently large

enough to maintainadequate log switch information to resolve

archivelog gaps.

-------------------------------------------------------------

1.备库上面查看丢失的归档

idle> SELECTTHREAD#, LOW_SEQUENCE#, HIGH_SEQUENCE# FROM V$ARCHIVE_GAP;

THREAD# LOW_SEQUENCE# HIGH_SEQUENCE#

----------------------- --------------

1 70 72

2.主库查看归档是否存在

先查看文件在系统中的位置

sys@DEX> SELECT NAME FROM V$ARCHIVED_LOG WHERE THREAD#=1 AND DEST_ID=1 AND SEQUENCE# BETWEEN 70 AND 72;

NAME

------------------------------

/u01/arch1/1_70_768793323.arc

/u01/arch1/1_71_768793323.arc

/u01/arch1/1_72_768793323.arc

使用系统命令查看，，如果看到没有找到文件，那么进入下面的阶段。

file /u01/arch1/1_70_768793323.arc

/u01/arch1/1_70_768793323.arc:cannot open `/u01/arch1/1_70_768793323.arc' (No such file or directory)

3.备库查看丢失的归档时的scn号

idle> select current_scn from v$database;

CURRENT_SCN

-----------

1102063

4.主库创建基于丢失归档scn号为起始的增量备份（要确定主库和备库的目标目录有足够的空间，这里使用/tmp文件夹）

RMAN> run{

BACKUP DEVICE TYPEDISK INCREMENTAL FROM SCN 1102063 DATABASE

FORMAT '/tmp/stb_bk/%U_for_stb.bk'

include current controlfile for standby ;

}