redo logs and standby database
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Thread: redo logs and standby database

  1. #1
    Join Date
    Apr 2001
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    257

    Question redo logs and standby database

    Hi,

    Environment: Oracle 8.1.7.3 on Win2k with Primary/Standby setup

    I am trying to determine the size and number of redo logs for my primary database. I have a standby database set up for it. When I observe the current log switch, the most frequent log switch occurred within 6 minutes and the redo log size is currently 20MB each. I am thinking about shrinking it down to 3-5MB and in the meantime increasing the number of log groups from 3 to 6. However, as far as I know, archiving is not immediately activated when a log switch occurs. I worry if there are too many unarchived redo logs and the primary system fails, I will lose big. Does anybody have any suggestions/rule of thumbs to balance it out?

    Thanks,

  2. #2
    Join Date
    Jul 2002
    Location
    California
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    If your standby database is a Managed standby database, Oracle will transfer the logs to the standby machine and apply them automatically for you.

    The other option is to force a log switch every N minutes, transfer(FTP) the logs via script to the standby machine and then have a script on the standby machine apply these logs.
    alapps

    Fast, Cheap, Reliable... Pick Two(2)

  3. #3
    Join Date
    Apr 2002
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    Shenzhen, China
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    If you resize your redo logfile to 5M, the Log Switch and Checkpoint will happen within 1.5 minutes. It is definitely too frequent for a high-update system.

    If you wanna protect your data in a more safe level, just configure your standby solution in Rapid Protection mode, which use LGWR to transfer redo log to standby server in ASYNC mode.
    Oracle Certified Master - September, 2003, the Second OCM in China
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  4. #4
    Join Date
    Apr 2001
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    257
    Sorry I forgot to mention it's not Managed standby but in Manual Recovery mode. We can't afford Enterprise edition of Oracle, which allows Managed standby.

    Isn't "Rapid Protection mode" only available in Oracle 9i Data Guard?

    Thanks,

  5. #5
    Join Date
    Apr 2002
    Location
    Shenzhen, China
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    Then I see, However, even if your primariy run to fail, the online redo logfiles are available for you to copy them to the standby site. Then you will lose nothing.

    How about replication in transaction level solution?
    Last edited by Calvin_Qiu; 11-22-2002 at 02:25 AM.
    Oracle Certified Master - September, 2003, the Second OCM in China
    *** LOOKING for PART TIME JOB***
    Data Warehouse & Business Intelligence Expert
    MCSE, CCNA, SCJP, SCSA from 1998

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