4 Replies Latest reply: May 21, 2014 4:07 AM by ma365 RSS

    Simulate Transport Lag.




      Can anyone suggest a way to simulate a transport lag in Data Guard?


      We have a RAC primary and RAC standby. I'd like to test that the monitoring I have in place alerts when there is a problem that causes the transport lag reported in v$dataguard_stats to increase.


      I have tested the apply lag by stopping the mrp process. This causes the value of 'apply lag' in v$dataguard_stats to increase the longer the mrp is stopped. I have tried stopping the standby listener to see if this would cause 'transport lag' to increase but it didn't have the desired effect.


      Any tips on how to introduce a transport lag for testing purposes?


      The enivironment is running on RHEL6.



        • 1. Re: Simulate Transport Lag.

          Have you tried to disable the log_archive_dest used for the transport?


          Are you using the DG Broker?



          • 2. Re: Simulate Transport Lag.



            Adding a delay might work.


            Setting the NIC to half duplex might also work. Or unplug the cable for a while.


            Defer until you have a large backlog might work ( or with the broker command if using )


            alter system set log_archive_dest_state_2=defer; 


            Best Regards



            • 3. Re: Simulate Transport Lag.

              I am using Data Guard Broker. I have tried setting TRANSPORT-OFF in the Broker configuration and I have also tried setting log_archive_dest_state_2 to DEFER on all primary RAC nodes. I left the primary in this state for over an hour but neither of these changes d the transport lag reported in v$dataguard_stats to increase.


              I've also turned off real time apply whilst I'm testing this.


              Starting to wonder how the transport lag value in v$dataguard_stats is calculated.



              • 4. Re: Simulate Transport Lag.

                I'm going to try changing the NIC settings this morning. Thanks for the suggestion.