Dataguard failover - what went wrong here??
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  1. #1
    Join Date
    Oct 2002
    Posts
    807

    Dataguard failover - what went wrong here??

    I have the below DG configuration replicating to a physical standby in a Maximum performance mode (using LGWR as the Xptmode).

    I had to perform/simulate a failover to the standby in this case. So I "DEFER"ed the appropriate log_archive_dest_state_n on the primary (I didn't disable the DG configuration)..and then went about activating the standby database. Here's a cut n paste of what I did..in exact sequence (the commands were typed one after the other rapidly). Why in the world did the SWITCHOVER (failover rather) throw errors the first 2 times..and then work in the end? Yes, it's on windows..

    Thanks.


    Microsoft Windows 2000 [Version 5.00.2195]
    (C) Copyright 1985-2000 Microsoft Corp.
    C:\Documents and Settings\Administrator>set ORACLE_SID=PRODDB
    C:\Documents and Settings\Administrator>sqlplus "sys as sysdba"
    SQL*Plus: Release 9.2.0.6.0 - Production on Tue May 24 14:56:10 2005
    Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
    Enter password:
    Connected to:
    Oracle9i Enterprise Edition Release 9.2.0.6.0 - Production
    With the Partitioning, OLAP and Oracle Data Mining options
    JServer Release 9.2.0.6.0 - Production

    SQL> SELECT THREAD#, LOW_SEQUENCE#, HIGH_SEQUENCE# FROM V$ARCHIVE_GAP;

    no rows selected

    SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE FINISH;

    Database altered.

    ---->>>> NICE!

    SQL>
    SQL>
    SQL> ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY;
    ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY
    *
    ERROR at line 1:
    ORA-16139: media recovery required

    ---->>>>> WHAT THE HECK??!!


    SQL> ALTER DATABASE ACTIVATE STANDBY DATABASE;
    ALTER DATABASE ACTIVATE STANDBY DATABASE
    *
    ERROR at line 1:
    ORA-00261: log 5 of thread 1 is being archived or modified
    ORA-00312: online log 5 thread 1: 'D:\ORACLE\ORADATA\PRODDB\PRODDB_SRL1.F'

    --->>> WHATEVER..


    SQL> ALTER DATABASE ACTIVATE STANDBY DATABASE SKIP STANDBY LOGFILE;
    ALTER DATABASE ACTIVATE STANDBY DATABASE SKIP STANDBY LOGFILE
    *
    ERROR at line 1:
    ORA-00261: log 5 of thread 1 is being archived or modified
    ORA-00312: online log 5 thread 1: 'D:\ORACLE\ORADATA\PRODDB\PRODDB_SRL1.F'

    ---->>>>> WHAT?? WHY IS IT BEING MODIFIED?!! I DEFER'ED the log_arch_dest_state on the primary..SHOULDN'T THAT TAKE CARE OF THIS? NOTE : THE "ALTER DATABASE RECOVER MANAGED STANDBY DATABASE FINISH;" was successful. YET, IT THROWS THIS ERROR!


    SQL> alter database recover managed standby database finish skip wait;
    alter database recover managed standby database finish skip wait
    *
    ERROR at line 1:
    ORA-00283: recovery session canceled due to errors
    ORA-00261: log 5 of thread 1 is being archived or modified
    ORA-00312: online log 5 thread 1: 'D:\ORACLE\ORADATA\PRODDB\PRODDB_SRL1.F'

    ----->>>> OKAY...


    SQL> shutdown immediate;
    ORA-01109: database not open

    --->>> AM SHUTTING DOWN STANDBY AS A LAST RESORT TO KILL / STOP THAT SRL THREAD FROM THE PRIMARY

    Database dismounted.
    ORACLE instance shut down.
    SQL> startup nomount;
    ORACLE instance started.

    Total System Global Area 1242638604 bytes
    Fixed Size 456972 bytes
    Variable Size 528482304 bytes
    Database Buffers 713031680 bytes
    Redo Buffers 667648 bytes
    SQL> alter database mount standby database;

    Database altered.

    SQL> RECOVER MANAGED STANDBY DATABASE FINISH;
    Media recovery complete.
    SQL> ALTER DATABASE ACTIVATE STANDBY DATABASE;
    ALTER DATABASE ACTIVATE STANDBY DATABASE
    *
    ERROR at line 1:
    ORA-16132: An error occurred during activation of the standby.


    ---->>>>>>>>>> AAAAAHHHHH

    SQL> shutdown immediate
    ORA-01109: database not open

    --->>>>> HERE I GO AGAIN

    Database dismounted.
    ORACLE instance shut down.
    SQL> startup nomount
    ORACLE instance started.

    Total System Global Area 1242638604 bytes
    Fixed Size 456972 bytes
    Variable Size 528482304 bytes
    Database Buffers 713031680 bytes
    Redo Buffers 667648 bytes
    SQL> recover managed standby database cancel;
    ORA-16136: Managed Standby Recovery not active

    -->>> I SEE..(I ENTERED THIS COZ THE DATABASE AUTOMATICALLY GETS MOUNTED AND SET IN A MANAGED RECOVERY MODE once I startup "NOMOUNT" even..)


    SQL> recover standby database;
    ORA-00283: recovery session canceled due to errors
    ORA-16157: media recovery not allowed following successful FINISH recovery

    --->>>> JUST CHECKING IF IT'LL ALLOW ME TO MANUALLY RECOVER. AS YOU CAN SEE, THE DATABASE IS ALREADY MOUNTED.


    SQL> recover managed standby database;
    ORA-00283: recovery session canceled due to errors
    ORA-16157: media recovery not allowed following successful FINISH recovery

    --->>> OKAY, I CANNOT ISSUE RECOVER, ONCE "FINISH"ed..got it.

    SQL> ALTER DATABASE COMMIT TO SWITCHOVER TO primary;

    Database altered.

    --->>>>> HOLY COW! WHY DID IT WORK THIS TIME, BUT NOT THE LAST 2 TIMES?!!

    SQL> shutdown immediate;
    ORA-01507: database not mounted

    ORACLE instance shut down.
    SQL> startup
    ORACLE instance started.

    Total System Global Area 1242638604 bytes
    Fixed Size 456972 bytes
    Variable Size 528482304 bytes
    Database Buffers 713031680 bytes
    Redo Buffers 667648 bytes
    Database mounted.
    Database opened.

    ---->>>> SWEET!
    Last edited by Axr2; 05-24-2005 at 06:48 PM.

  2. #2
    Join Date
    Aug 2000
    Location
    Jolo, Sulu
    Posts
    639
    im sure u just missed something
    thats what i do all the time...and learned from experience...
    TRY AND TRY UNTIL YOU SUCCESS
    Last edited by kris123; 05-24-2005 at 09:57 PM.

  3. #3
    Join Date
    Oct 2002
    Posts
    807
    Originally posted by kris123
    im sure u just missed something
    thats what i do all the time...and learned from experience...
    TRY AND TRY UNTIL YOU SUCCESS
    WTF?

  4. #4
    Join Date
    Nov 2000
    Location
    Pittsburgh, PA
    Posts
    4,015
    Do you need to do log switches on the primary and or force the secondary to sync up before making the secondary database active? Also, do you need to change the control file before you activate the server.

    fyi, It has been awhile since I have mucked with standby servers.
    this space intentionally left blank

  5. #5
    Join Date
    Oct 2002
    Posts
    807
    Originally posted by gandolf989
    Do you need to do log switches on the primary and or force the secondary to sync up before making the secondary database active? Also, do you need to change the control file before you activate the server.

    fyi, It has been awhile since I have mucked with standby servers.
    If the logXptMode were ARCH (max availability mode), yes you would need to switch archivelogs..and everything in online redologs is history.

    With max performance and LGWR mode, you don't need to switch logs..coz it uses SRLs (standy redologs). When LGWR Xpt gets hosed it automatically switches to max availability mode.

    As for controlfile stuff..it is taken care of when you activate the standby.

    In my case, the failover worked -- it eventually did what I asked it to (i blew my online redologs..but thats okay by me). But I don't get why it complained the first couple of times..and worked the 3rd time.

    PS : I've performed real failovers / switchovers many times in past..never faced this before.

  6. #6
    Join Date
    Jan 2008
    Posts
    17
    hi gurus of dataguard ,
    i have 2 query plz help

    i have data guard configured in maximum protection mode and arch and
    no standby logfiles, for
    failover what should i follow
    1) alter database recover managed standby database skip standby log files;
    or
    alter database recover managed standby finish skip standby log file;
    if i follow option a) do i need to do option b) as well ?

    2) is it to be done at mount or nomount stage??

  7. #7
    Join Date
    Dec 2007
    Posts
    55
    i have data guard configured in maximum protection mode and arch and
    no standby logfiles, for
    failover what should i follow
    1) alter database recover managed standby database skip standby log files;
    or
    alter database recover managed standby finish skip standby log file;
    if i follow option a) do i need to do option b) as well ?
    sql>alter database recover managed standby database skip standby log files;

    does gracefull failover even without standby redologs .
    if i follow option a) do i need to do option b) as well ?
    nope you dont have too,
    aftre that just do sql>alter database commit to switchover to primary;

    2)should be mounted.

    Regards
    Last edited by monto1; 01-18-2008 at 04:36 PM.

  8. #8
    Join Date
    Jan 2001
    Posts
    2,828
    Quote Originally Posted by hafeezkalsekar
    hi gurus of dataguard ,
    i have 2 query plz help

    i have data guard configured in maximum protection mode and arch and
    no standby logfiles, for
    failover what should i follow
    AFAIK you need to have standby logs if you want to use maximum protection mode


    regards
    Hrishy

  9. #9
    Join Date
    Jan 2008
    Posts
    17

    data guard

    hi thnk for reply

    so monto these is what i suppose to do ??

    1) alter database recover managed standby skip standby logfiles;

    2) alter database commit to switchover to primary ;

    but what about the finish command is it not neccessary ??

  10. #10
    Join Date
    Jun 2000
    Location
    Madrid, Spain
    Posts
    7,447
    Quote Originally Posted by hafeezkalsekar
    1) alter database recover managed standby database skip standby log files;
    or
    alter database recover managed standby finish skip standby log file;
    if i follow option a) do i need to do option b) as well ?

    2) is it to be done at mount or nomount stage??
    that is BS because you need standby logfiles to use maximum protection

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