knowledge transfer on oracle rman restore

8/9/2019 Knowledge Transfer on ORACLE RMAN restore

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A hands-on knowledge transfer session on restore scenariosOctober 2009

Nikos PlevrisPrincipal Service Delivery Manager


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Agenda

The story The actors Hints & Tips

Scenario 1 Scenario 2 Scenario 3 Scenario 4

The end


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The story

Manager , DBAs.

o Manager " . !! , ,

. !

..". , , PC . . , , " , ". ' .

. " , ". manual, Installer (OUI)

, , ',

. ...


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Little 4 Pigs DBAs YPA :=... - ! PE := -

! B32 32, Oracl Pili8 := 8 -

!

The Wolf Mr Leonidas


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Its all about this!


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Scenario 1 How to fix

For permanent media failures, here are theinstructions for dropping and re-creating onemember of an online redo log group:1. Identify the online redo log fileexperiencing media failure.2. If the online redo log file is part of thecurrent online log group, thenSQL>alter system switch logfile3. Drop the damaged member.SQL> alter database drop logfile

member '';4. Add a new member to the group.SQL> alter database add logfile

member '\directory\member>' reuse togroup ;


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Scenario 2 s adventure

.

DBA, . PIG2. :$ rm *.log : ALL members of the logfile

group 2 were removed. , errors . ...

Hints & Tips1. Inspect the alert.log file todetermine which online redo log

files have experienced a mediafailure.2. Query V$LOG and V$LOGFILE todetermine the status of the loggroup CURRENT or ACTIVE orINACTIVE.3. Then see next slide for

details on how to fix the remainingfailed member(s).


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The 4 Little pigs should know


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Hints & TipsSee alrt.log for ORA-1578 errors RMAN>backup validate datafile;

Use the dbverify utility to validatewhich datafile has a corrupt block:$ dbv file= blocksize=8192

Use viewV$DATABASE_BLOCK_CORRUPTION toidentify corruption details

Scenario 3 s adventure

, ., 32. ? To corrupt some blocks of thesalary table in the database PIG3 ."

, 32 . 5 . - , . " !

,

errors. The query was:select * from scott.salgrade;


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Scenario 3 How to fix

Identify object with corruption fromDBA_EXTENTS, DBA_SEGMENTSSQL>SELECT tablespace_name,segment_type, owner, segment_nameFROM dba_extents WHERE file_id =

and 125021 between block_id AND block_id + blocks - 1;

Use the RMAN recover command to restoreblock in datafile (if

youre using Oracle Database 10 g orOracle9 i , then use the RMAN blockrecover command):RMAN> recover datafile block

; Important RMAN will attempt to restore the block from either

a full backup, or a level 0 backup, or an image copybackup generated by backup as copy command.

After the block has been restored, any requiredarchived redo logs must be available to recover theblock.

RMAN cant perform block media recovery usingincremental level 1 (or higher)

backups.


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Scenario 4 s adve nture , . ! . oracle UNIXaccount password citrix Metaframe login Pili8 server,

PIG4. DROP TABLE

. . . ,

archived logs. , Pili8 alertemail : " error ORA-00942: table or view does not exist"

26/10 09:38 . Pili8 !

Hints & Tips-Time Sequence of events toconsider:

1.DROP TABLE (t0) > Point-In-Time-Recovery2.Missing archived log (t1) ->Not needed3.Generated archived logs) ->Apply them


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Scenario 4 How to fixQuery v$log_history, v$archived_log to identifytime/SCNUse RMAN to restore db until time/SCNRMAN> run {2> set until time "to_date('25/10/200905:32:58','dd/mm/yyyy HH24:mi:ss')";3> restore database;4> recover database;5> }Open db with resetlogs.Before opening db withresetlogs, the checkpoint SCN for all online datafiles

must be identicalSQL> select file#, status,checkpoint_change#,to_char(checkpoint_time,'dd-mon-rrrrhh24:mi:ss') from v$datafile_header;To tackle error RMAN-06059:expected archived lognot found RMAN>crosscheck {backup|archivelog all}; RMAN>delete noprompt obsolete;

RMAN>delete expired archivelog all;Important Immediately backup database/archive logs after

incomplete recovery The V$DATAFILE_HEADER view uses the physical

datafile on disk as its source. The V$DATAFILEview uses the control file as its source.


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My dearest little ones keep in mind 1


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My dearest little ones keep in mind 2


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The end..

Be tha nkful for problems. If they were less difficult ,someo ne else with less ability might have your job.

knowledge transfer on oracle rman restore

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