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  1. #1
    Join Date
    Aug 2003
    Posts
    6

    Unanswered: Redo.logs save online for Disaster

    Hi @all
    i search for a methode to save redologs online via network.
    How can i made it without close the database. And how can I rebuild the database after a disaster? And which files i must have absolutly to
    redo after disaster.

    Thanx M@tes

    By the WAY It's for oracle 8.1.7

  2. #2
    Join Date
    Mar 2002
    Location
    Ireland
    Posts
    181
    Hi M@tes,
    If you put the database in archive log mode.
    And the bast backup strategy is to use RMAN.

    This will backup your database while it's up and will backup your archived redo logs and then delete them so they don't fill up your file system.

    You can backup all of the above to disk or tape (if you have the relevant software / tape drives.)

    Hope this helps,
    Breen.

  3. #3
    Join Date
    Aug 2003
    Posts
    6

    @ breen

    OK. I write the redos to HD.
    and then?
    Is it this?

    "alter system switch logfile;"

    After this I can save(copy,move) the old redologs. New one will create. Ok!

    What I must have to rebuild with the redos the database after disaster.
    1. Complete Backup of the maschine.
    2. all redologs
    3. ????
    4. ???
    ..
    .
    at last time!

  4. #4
    Join Date
    Mar 2002
    Location
    Ireland
    Posts
    181
    At the sql prompt type

    SQL> archive log list;

    This will tell you if you are in archive log mode and will show you the directory where the archived logs will go.

    If not then type

    SQL> alter system archive log start;

    Now you are archiving.

    You will want to backup all your datafiles - this can be done most effectively using RMAN.

    If you are not going to use RMAN then you can do hot backups:

    SQL> alter tablespace TS_NAME begin backup;

    then on the OS
    unix
    $ cp /db/u02/datafile.dbf /backup/datafile_bk.dbf

    Windows:
    c:\> ocopy c:\db\u02\datafile.dbf d:\backup\datafile_bk.dbf

    then
    SQL> ALTER TABLESPACE TS_NAME end backup;

    do this for all tablespaces then

    SQL> alter system switch logfile;

    Ta da.

    Rgs,
    Breen.

  5. #5
    Join Date
    Jul 2003
    Posts
    15
    In general you don't want to backup the online redo logs. The reason being is that if you accidentally overwrite the current online redo logs with older copies from your backup then you can't do a complete recovery. To safeguard against problems with your online redo logs you want to be sure and have multiple members in each redo log group and have the members on separate drives. RMAN deliberately won't backup online redo logs specifically because of this possibility.

    That being said, if you really do want to backup your redo logs the only way to do so reliably is with a cold backup, ie, with the database shutdown.

  6. #6
    Join Date
    Mar 2002
    Location
    Ireland
    Posts
    181
    Hi cz0763,

    We are talking about backing up archived redo logs.

    Rgs,
    Breen.

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