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Recover physical standby database after loss of archive log – roll forward(转)

原创 Linux操作系统 作者:aaqwsh 时间:2012-03-25 15:15:28 0 删除 编辑

The tutorial shows an example of how we can use RMAN incremental backup to recover the standby in such a scenario.

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Source 
 DBNAME   PRODDB 
 Oracle Home  /u01/ora10g
 Archive Dest  /u02/PRODDB/arch
 
Destination 
 DBNAME   PRODDB
 Oracle Home  /u01/ora10g
 Archive Dest  /u02/PRODDB/arch
  1. Synch primary and standby. Defer application of logs on standby.
  2. Let us now create some dummy tables and switch the logfile on primary. This is the log file that would be needed for recovery
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    {PRIMARY} /u01/ora10g/backup $ sqlplus
     
    SQL*Plus: Release 10.2.0.3.0 - Production on Wed May 19 12:37:34 2010
     
    Copyright (c) 1982, 2006, Oracle.  All Rights Reserved.
     
    Enter user-name: demo/demo
     
    Connected to:
    Oracle Database 10g Enterprise Edition Release 10.2.0.3.0 - 64bit Production
    With the Partitioning, OLAP and Data Mining options
     
    SQL> select * from tab;
     
    TNAME                          TABTYPE  CLUSTERID
    ------------------------------ ------- ----------
    OBJLIST                        TABLE
     
    SQL> create table object_list as select * from dba_objects        
      2  union select * from dba_objects;
     
    Table created.
     
    SQL> conn / as sysdba
    Connected.
    SQL> archive log list
    Database log mode              Archive Mode
    Automatic archival             Enabled
    Archive destination            /u02/PRODDB/arch/
    Oldest online log sequence     59
    Next log sequence to archive   61
    Current log sequence           61
    SQL> alter system switch logfile;
     
    System altered.
     
    SQL> archive log list;
    Database log mode              Archive Mode
    Automatic archival             Enabled
    Archive destination            /u02/PRODDB/arch/
    Oldest online log sequence     60
    Next log sequence to archive   62
    Current log sequence           62
    SQL>
  4. Get the current SCN of standby database
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     STBYHOST(PRODDB)SQL >select current_scn from v$database;
     
                          CURRENT_SCN
     --------------------------------
                        7765466164256
     
     STBYHOST(PRODDB)SQL >
  6. To find out which is the next archive log the standby database needs for recovery, run the recover command on the standby database without applying the archive logs
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     STBYHOST(PRODDB)SQL >recover standby database ;
     ORA-00279: change 7765466164257 generated at 05/19/2010 11:55:11 needed for
     thread 1
     ORA-00289: suggestion : /u02/PRODDB/arch/PRODDB_1_717173775_60.arc
     ORA-00280: change 7765466164257 for thread 1 is in sequence #60
     
     
     Specify log: {=suggested | filename | AUTO | CANCEL}
     CANCEL
     Media recovery cancelled.
     STBYHOST(PRODDB)SQL >

    Archive Sequence 60 is needed for recovery. Let us now assume that this archive log is not available on disk or on tape backup.

  8. Use SCN in step 3 to take an incremental backup on disk on primary database
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    {PRIMARY} /u01/ora10g/backup $ export ORACLE_SID=PRODDB
    {PRIMARY} /u01/ora10g/backup $ rman target /
    .... 
    RMAN> BACKUP INCREMENTAL FROM SCN 7765466164256 DATABASE FORMAT '/u01/ora10g/backup/proddb_standby_%U' tag 'proddb_standby';
    Starting backup at 19-MAY-10
    using channel ORA_DISK_1
    RMAN-06755: WARNING: datafile 5: incremental-start SCN is too recent; using checkpoint SCN 7765465268142 instead
    RMAN-06755: WARNING: datafile 6: incremental-start SCN is too recent; using checkpoint SCN 7765465268142 instead
    channel ORA_DISK_1: starting full datafile backupset
    channel ORA_DISK_1: specifying datafile(s) in backupset
    input datafile fno=00003 name=/restorevol/BACKUPREST/PRODDB/data/PRODDB_SYSAUX_01.dbf
    input datafile fno=00005 name=/restorevol/BACKUPREST/PRODDB/data/PRODDB_TS_LMTDATA_01
    skipping datafile 00005 because it has not changed
    input datafile fno=00006 name=/restorevol/BACKUPREST/PRODDB/data/PRODDB_TS_LMTDATA_02.dbf
    skipping datafile 00006 because it has not changed
    input datafile fno=00001 name=/restorevol/BACKUPREST/PRODDB/data/PRODDB_SYSTEM_01.dbf
    input datafile fno=00002 name=/restorevol/BACKUPREST/PRODDB/data/PRODDB_UNDOTBS_01.dbf
    input datafile fno=00004 name=/restorevol/BACKUPREST/PRODDB/data/PRODDB_TOOLS_01.dbf
    channel ORA_DISK_1: starting piece 1 at 19-MAY-10
    channel ORA_DISK_1: finished piece 1 at 19-MAY-10
    piece handle=/u01/ora10g/backup/proddb_standby_fjle2nl3_1_1 tag=proddb_standby comment=NONE
    channel ORA_DISK_1: backup set complete, elapsed time: 00:01:55
    Finished backup at 19-MAY-10
  10. Copy backupiece to standby database server and catalog in standby controlfile
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    {STBYHOST} /u01/ora10g/backup/PRODDB $ scp ora10r3@PRIMARY:/u01/ora10g/backup/proddb_standby_fjle2nl3_1_1 .                
    Password: 
    Password: 
    proddb_standby_fjle2nl3_ 100% |********************************************************************************************|  5848 KB    00:00    
    {STBYHOST} /misuatdata/PRODDB $ pwd
    /misuatdata/PRODDB
    {STBYHOST} /u01/PRODDB $ rman target / 
     
    Recovery Manager: Release 10.2.0.3.0 - Production on Wed May 19 13:04:30 2010
     
    Copyright (c) 1982, 2005, Oracle.  All rights reserved.
     
    connected to target database: PRODDB (DBID=2326455671, not open)
     
    RMAN> CATALOG START WITH '/u01/ora10g/backup/PRODDB/proddb_standby';           
     
    searching for all files that match the pattern /u01/ora10g/backup/PRODDB/proddb_standby
     
    List of Files Unknown to the Database
    =====================================
    File Name: /u01/ora10g/backup/PRODDB/proddb_standby_fjle2nl3_1_1
     
    Do you really want to catalog the above files (enter YES or NO)? YES
    cataloging files...
    cataloging done
     
    List of Cataloged Files
    =======================
    File Name: /u01/ora10g/backup/PRODDB/proddb_standby_fjle2nl3_1_1
     
    RMAN> exit
     
     
    Recovery Manager complete.
  12. Recover standby from RMAN
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    RMAN> RECOVER DATABASE NOREDO
    2> ;
     
    Starting recover at 19-MAY-10
    using target database control file instead of recovery catalog
    allocated channel: ORA_DISK_1
    channel ORA_DISK_1: sid=148 devtype=DISK
    datafile 5 not processed because file is read-only
    datafile 6 not processed because file is read-only
    channel ORA_DISK_1: starting incremental datafile backupset restore
    channel ORA_DISK_1: specifying datafile(s) to restore from backup set
    destination for restore of datafile 00001: /u02/PRODDB/oradata/data/PRODDB_SYSTEM_01.dbf
    destination for restore of datafile 00002: /u02/PRODDB/oradata/data/PRODDB_UNDOTBS_01.dbf
    destination for restore of datafile 00003: /u02/PRODDB/oradata/data/PRODDB_SYSAUX_01.dbf
    destination for restore of datafile 00004: /u02/PRODDB/oradata/data/PRODDB_TOOLS_01.dbf
    channel ORA_DISK_1: reading from backup piece /u01/ora10g/backup/PRODDB/proddb_standby_fjle2nl3_1_1
    channel ORA_DISK_1: restored backup piece 1
    piece handle=/u01/ora10g/backup/PRODDB/proddb_standby_fjle2nl3_1_1 tag=proddb_standby
    channel ORA_DISK_1: restore complete, elapsed time: 00:00:16
    Finished recover at 19-MAY-10
     
    RMAN>
  14. Refresh controlfile of standby from production
  15. On production

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    SQL> alter database create standby controlfile as '/tmp/proddb_stby.ctl';
     
    Database altered.
     
    SQL>

    On standby, copy the controlfile from production

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    {STBYHOST} /u02/PRODDB/oradata/cntrl $ scp ora10r3@PRIMARY:/tmp/proddb_stby.ctl .
    Password: 
    proddb_stby.ctl        100% |********************************************************************************************| 14096 KB    00:01    
    {STBYHOST} /u02/PRODDB/oradata/cntrl $

    Change init.ora

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    control_files = ('/u02/PRODDB/oradata/cntrl/proddb_stby.ctl')
  16. Startup and see recovery point
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    STBYHOST(PRODDB)SQL >recover standby database;
    ORA-00279: change 7765466166167 generated at 05/19/2010 12:54:59 needed for
    thread 1
    ORA-00289: suggestion : /u02/PRODDB/arch/PRODDB_1_717173775_62.arc
    ORA-00280: change 7765466166167 for thread 1 is in sequence #62
     
     
    Specify log: {=suggested | filename | AUTO | CANCEL}

    You can see that the recovery has skipped archive 60 and 61, which were part of the incremental backup.

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