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Former Member

Difference between the LOG modes (overwrite vs off)

Hi All;

Can somebody explain the difference between:

Log Overwrite mode

Log Normal

Log Off

Which needs to be backed up? Performance between the modes?

I have a training server that we Incr backup nightly. It is not a problem if the days work is lost due to some failure....but it is important (if no failure) to have the trainees work saved for the next day..... do I need logs?

Thanks

Tony

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    author's profile photo Former Member
    Former Member
    Posted on Dec 04, 2007 at 06:44 PM

    Basically

    Log Overwrite mode

    When the log file is full , instead of having a log full situation , it is overwritten.

    You dont have a log backup to restore for your last changes made. You dont need to backup it up.

    Log Normal

    All changes are store in the log queue and when the log queue is full it is passed to the log segment. If no backups are made to the log segmet either by autologbackup or manual backup you end up with a log full situation which you need to make a manual log backup to make the DB available for working.So backup is needed, and then you are available to restore the last changes.

    Log Off

    No logging at all is made, this is bad, cause if some trasnaccions where writting something and DB crashes , when you restart it the DB cannot reproduce them if they were in the log queue for processing.

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  • Posted on Dec 03, 2007 at 06:40 PM

    Hello Tony,

    Please see the documents :

    http://maxdb.sap.com/currentdoc/default.htm -> Basic Information

    ->Administration -> Backing Up and Restoring -> Backing Up Log Entries

    &&

    http://maxdb.sap.com/currentdoc/default.htm -> Basic Information

    -> Concepts of the Database System

    ->Creating and Configuring a Database Instance

    -> Log Settings

    If you are SAP customer, please overview the SAP note::

    869267 FAQ: MaxDB LOG area

    to find answers on your questions.

    Thank you and best regards, Natalia Khlopina

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