3 Replies Latest reply: Mar 18, 2013 11:16 AM by sandy121 RSS

    Few questions

    997381
      Hello,

      Please do excuse me for these easy questions as I am very new to Data guard technology.

      1)Can Gap detection and resolution be possible without setting FAL_server or FAL_Client on the the standby? (Version 10.2.0.4 & 11.2.0.2)

      2)Is there any relationship between LGWR & LNS?

      3)What impact does NOARCHIVELOG mode have on standby database?

      Thanks in advance

      With regards
        • 1. Re: Few questions
          mseberg
          Hello;
          Can Gap detection and resolution be possible without setting FAL_server or FAL_Client on the the standby? (Version 10.2.0.4 & 11.2.0.2)
          You can monitor a resolve a gap without these parameters. Manually for example.

          Use a query like this to check :

          http://www.visi.com/~mseberg/data_guard/monitor_data_guard_transport.html
          Is there any relationship between LGWR & LNS? 
          On the Primary LNS collects redo data from the online redo log files. The log writer process never waits for the LNSn for any reason in release 10.2. But in I believe in 11 if you use SYNC LGWR will wait for acknowledgement from the LNS before telling the client a commit has occurred.
          Oracle 10 is pretty old at this point and I cannot tell details without referring to the Oracle docs.

          The LGWR process can be used to transmit redo data to remote destinations.

          What impact does NOARCHIVELOG mode have on standby database?
          The biggest impact is your Standby database is not ready for Primary mode. The NOARCHIVELOG question has come here 3 times in the past week. My question is what advantage is this? A Standby mode database applies Archive from a Primary. If this leaves a copy on the Standby you can clean it up as soon as it applied using several well documented methods.


          Best Regards

          mseberg
          • 2. Re: Few questions
            Lonion
            1)if you don't set the two parameters , you should observe by yourself when archive log gap occurs , then copy archive log gap to the standby database and register them.

            2)just like mseberg said .

            3) i think it must impact standby database .

            From Document : 6.3 Applying Redo Data to Physical Standby Databases | http://docs.oracle.com/cd/B19306_01/server.102/b14239/log_apply.htm#i1020855
            look at the following statement :
            By default, the redo data is applied from archived redo log files.

            If NOARCHIVELOG mode have on standby database , where archived redo log files come from ?
            • 3. Re: Few questions
              sandy121
              What I have read that starting from Oracle 11g onwards "The LGWR process can be used to transmit redo data to remote destinations" is a total myth. LNS (Log Writer Network Server) alone is responsible for redo transport services, please correct me if I am wrong in my understanding.