Loss of Online redo !
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Thread: Loss of Online redo !

  1. #1
    Join Date
    Apr 2001
    Posts
    6

    Question

    We have oracle server version 8.0.5 & it is OLTP server & running in archive log mode. Yesterday we faced a serious problem of REDO file corruption while long running trans. ( Disk had hardware fault). After replacing HDD , we are unable to recover database up to the failure point though we had applied all archive logs.

    Note: We have only two redo groups having two members.

    Pls. suggest to recover up to last running trans.




  2. #2
    Join Date
    Jun 2000
    Location
    Madrid, Spain
    Posts
    7,448
    well you had two members in the same corrupted disk?

  3. #3
    Join Date
    Nov 2000
    Posts
    89
    You'll have to specify everything if you want help. Where are the redo files ? If you multiplexed correctly, you have a good redo somewhere. The idea behind multiplexing is to write to 2 locations that are safely on different disks or even different controllers.

    It is unclear where you stand.

    -Roger

  4. #4
    Join Date
    Apr 2001
    Posts
    6

    Arrow

    Wel ! members of redolog are multiplexed on four different disks. Other members of redolog are healthy and good.

    I try to recover from healthy redolog member by standard
    procedure but can't successed. I don't know the other step by step procedure to fix this problem.

    Suppose members of redolog are not multiplexed then is there any way to fix this problem ?

    Pls. mention all req. steps to recover the same.

    Sandeep

  5. #5
    Join Date
    Mar 2000
    Location
    Chennai.Tamilnadu.India.
    Posts
    658

    Recovery: from Logs

    Hi, 20th April 2001 11:12 hrs chennai

    Still i dont see from your reply confirming you have redo log copy.

    Any how you can see the scenarios as follows.
    ===================

    If redo log or corrupted recovery to the time of failure may not be possible.However no data is lost under the following circumstances.

    I)The redo logs files lost are not current.
    II)The redo log had been archived.
    III)The database is properly configured with mirrored redo log files.

    Suppose members of redolog are not multiplexed ?as per your doubt the answer is you can as the reasons mentioned above.

    If not you cannot recover up to the last point then You have to follow this steps for that.

    You have to do CANCEL based recovery.

    1)Shutdown the DB.
    2)from the valid backup mount the instance
    3)Restore all datafiles from the most recent backup

    4)after checking the last redo log available from the archives
    identofy the log seq no and issue the command

    svrmgr>recover database until cancel

    5)Open the DB with Reset logs option
    6)Now the last data from the last commit has to be reentered.

    Note:
    ===

    Missing Archive:
    ===========
    a cpmplete recovery operation fails due to a bad or missing archived log.Recovery can be only completed to a time in the past prior to applying the archived logs

    Missing redo Logs:
    ============
    If the redo logs are not mirrored and you lost a redo log before it is archived,along with a datafile recovery cannot continue past the redo log.

    Cheers

    Padmam





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