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Thread: Hot Backup of Redolog files

  1. #1
    Join Date
    Mar 2002
    Posts
    171
    I am new to DBA.

    I am maintainting an Oracle 8i server.

    Can someone please explain step-by-step procedure with COMMANDS of how to take Hot backups of Redo Log files.

    Thanks in advance.

  2. #2
    Join Date
    Apr 2002
    Posts
    9
    You don't really gain anything getting a backup of an online redo log - they are open and not in a consistent state to be useful in a recovery.
    You should create multiple copies of redo log files on
    different physical device by command
    ALTER DATABASE ADD LOGFILE MEMBER ....

  3. #3
    Join Date
    Mar 2002
    Posts
    171
    Originally posted by uncleserg
    You don't really gain anything getting a backup of an online redo log - they are open and not in a consistent state to be useful in a recovery.
    You should create multiple copies of redo log files on
    different physical device by command
    ALTER DATABASE ADD LOGFILE MEMBER ....
    Thanks. Could you pls explain some details of how to do this.

  4. #4
    Join Date
    Apr 2002
    Posts
    9
    1. Connect to database as sysdba
    sqlplus /nolog
    connect sys/passwd as sysdba;
    2. Look at your redo log configuration
    SQL> select * from v$logfile;

    GROUP# STATUS TYPE
    ---------- ------- -------
    MEMBER
    ------------------------------------------------------
    1 ONLINE
    /u01/oracle/ora9i/oradata/ln9i/redo01.log

    2 STALE ONLINE
    /u01/oracle/ora9i/oradata/ln9i/redo02.log

    3 STALE ONLINE
    /u01/oracle/ora9i/oradata/ln9i/redo03.log


    There are 3 redo groups, each has one member.
    2. Add addition member to each group
    alter database add logfile member '/u00/oracle/ora9i/oradata/ln9i/redo01.log'
    to group 1;
    alter database add logfile member '/u00/oracle/ora9i/oradata/ln9i/redo02.log'
    to group 2;
    alter database add logfile member '/u00/oracle/ora9i/oradata/ln9i/redo03.log'
    to group 3;

    3.
    SQL> select * from v$logfile;

    GROUP# STATUS TYPE
    ---------- ------- -------
    MEMBER
    ----------------------------------------------
    1 ONLINE
    /u01/oracle/ora9i/oradata/ln9i/redo01.log

    2 STALE ONLINE
    /u01/oracle/ora9i/oradata/ln9i/redo02.log

    3 STALE ONLINE
    /u01/oracle/ora9i/oradata/ln9i/redo03.log
    1 INVALID ONLINE
    /u00/oracle/ora9i/oradata/ln9i/redo01.log

    2 INVALID ONLINE
    /u00/oracle/ora9i/oradata/ln9i/redo02.log

    3 INVALID ONLINE
    /u00/oracle/ora9i/oradata/ln9i/redo03.log

    Now each group has 2 members located on different disk.
    If disk with /u01 filesystem fails I can use copy of my redo
    logs on /u00.



  5. #5
    Join Date
    Dec 2000
    Location
    Ljubljana, Slovenia
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    4,439
    You should never back up your redo logs ever!
    Jurij Modic
    ASCII a stupid question, get a stupid ANSI
    24 hours in a day .... 24 beer in a case .... coincidence?

  6. #6
    Join Date
    Nov 2000
    Location
    greenwich.ct.us
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    9,092
    ...except, of course, in a cold backup.
    Jeff Hunter

  7. #7
    Join Date
    Jun 2001
    Location
    Helsinki. Finland
    Posts
    3,938
    Originally posted by marist89
    ...except, of course, in a cold backup.
    As far as I remember, even then Jurij neglects them opening with resetlogs, right Jurij?

    Oracle Certified Master
    Oracle Certified Professional 6i,8i,9i,10g,11g,12c
    email: ocp_9i@yahoo.com

  8. #8
    Join Date
    Aug 2000
    Posts
    462
    If you've done a proper cold backup (shutdown normal, transactional or immediate), then the database is shut down in a consistent state anyway, and the logs are not necessary for instance recovery. No resetlogs will be necessary to open a cold backup database. As long as you also backed up your control file . . .
    Oracle DBA and Developer

  9. #9
    Join Date
    Dec 2001
    Posts
    221
    if your database is in ARCHIVELOG mode then you have the backups.
    Santosh Jadhav
    8i OCP DBA

  10. #10
    Join Date
    Dec 2000
    Location
    Ljubljana, Slovenia
    Posts
    4,439
    Originally posted by julian
    Originally posted by marist89
    ...except, of course, in a cold backup.
    As far as I remember, even then Jurij neglects them opening with resetlogs, right Jurij?
    True. And its not just me - you'll never find RMAN to back up redo logs, not even with cold backups...
    Jurij Modic
    ASCII a stupid question, get a stupid ANSI
    24 hours in a day .... 24 beer in a case .... coincidence?

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