6 Replies Latest reply on Apr 20, 2018 11:50 AM by vlgmarchesini

    AF Collective synchronising only some Databases

    vlgmarchesini

      Hi,

       

      When creating an AF collective, is it possible to choose or delimit the databases to be synchronised in the secondary?

      I want high availability for an specific database (as shown in the picture below), one of the others is huge and I have hw/network constraints to create a collective for it.

       

       

       

      Thanks,

        • Re: AF Collective synchronising only some Databases
          Dan Fishman

          Victor it is not possible to replicate just one database.  PI AF Collectives use transnational replication to replicate the PIFD database.  A workaround, would be to install a second AF Server and use a different SQL Server instance, and only host one database. 

           

          There is also the PI System Connector, but it really is intended for a different purpose. 

          1 of 1 people found this helpful
          • Re: AF Collective synchronising only some Databases
            gregor

            Hello Victor,

             

            KB00634 - High Availability (HA) options for PI Asset Framework (PI AF) is definitely a resource you should read. Please note that we no longer recommend PI AF Server Collectives.

            • Re: AF Collective synchronising only some Databases
              sraposo

              Hi Victor,

               

              The name of the database also suggests that you are running calculations in AF. Please note that the secondary member of an AF Collective is read only due to the way SQL Transactional Replication works. As Gregor Beck mentioned, OSIsoft does not recommend AF Collectives as an AF HA option.

               

              Out of curiosity, what is your use case for AF HA? I think you may be better served by a different HA setup.

               

              Thanks,

              Seb

                • Re: AF Collective synchronising only some Databases
                  vlgmarchesini

                  Thank you Sebastien,

                   

                  I work in an ISO and we are using PI Analysis for real time calculations. Since those calculations are critical, we managed a workaround to keep it running initerruptly.

                   

                  I created a Powershell script that follow the steps below:

                       1. I export an xml file to a second AF server daily;

                       2. In this second AF server I have a database with the same name of the first "CalculosTR", I UNDO CHECK-OUT in this second database;

                       3. I import the xml file created from the first server to the second one, but I do not check-in, because if it was done, there would be two different analysis writing in the same tags.

                       4. In case of problems with server1, it is possible to check-in the changes in server2 and the analysis will keep running.

                   

                  The cons:

                       In case of problems I have to check-in manually the second server;

                       I am copying data from the first server to the second once a day.

                   

                  I am trying to find a more suitable solution for this tine but very important database.

                   

                  Any suggestions?

                   

                  PS: I am sorry for the time taken to reply, I was in a trip for business and had limitations to access internet.