4 Replies Latest reply on Jun 9, 2010 1:42 AM by gmoffett

    ACE not working with Collective


      Hi All,


      I am facing an issue with ACE connection. I am already in touch with OSISoft techsupport team (Call # 303737 )but want to discuss with everybody, so that if somebody has already faced this issue he/she can help in resolving it fast.


      The configuration is as follows :

      1. PI Servers as collective node. 1 primary and 1 secondary
      2. ACE Server is a separte machine with ACE Scheduler and class libraries.

      Everything was running fine but suddenly few days before Primary PIServer was down (Disk Crash). So everything (OPC Interfaces, Clients..etc) switched to connect to Secondary PIServer. ACE scheduler which was updating data on both the server perviously, stop updating data on secondary server from the day primary server is down. As per configuration, ACE should automatically switch to Secondary PIServer and calculations should not stop updating. But that is not happening.


      With Proper Buffering setup, ACE automatically sends data to all members in server collective. It was happening till the primary was working but from the day primary is down, it stop updating data to secondary PIServer also.


      Workaround we (Me and OSISoft techsupport team) did :

      1. Confirmed that Buffering is ON on ACE Server ---- ON and runnning
      2. Restart all the interfaces then Buffering subsystem including ACEscheduler. ------- succesfully restarted
      3. Checked connection of PIServer through PISDK. ---- Connecting to collective node as secondary piserver

      After all this work around, we found lot of messages in log files that "ACE not able to connect to PRIMARY PISERVER" and 1 message from ACENetScheduler.exe that "Failed to connect to server TABPICOLL : 8004078a" ---- TABPICOLL is the name of collective. Still there is no connection between ACEScheduler and Secondary PIServer.


      please Reply if somebody is aware of this.




      Prabhat Mishra

        • Re: ACE not working with Collective

          Hi Prabhat,


          The problem here is that given the current implementation of PI HA collective, ACE will need to connect to the primary server of the collective in order to start or stop calculations and hence you see the error as indicated by ACE scheduler and it does not proceed after that.


          The reason for this limitation is that the ACE calculation status and information are stored in the Module Database (MDB) structure of the PI server. When a calculation is started or stopped the status of the calculation is updated in the MDB. Given that it is a PI collective, the changes are made on the primary PI server and then replicated to the secondary server(s). We can't make changes on MDB of a seconday server and hence we can end up in a situation like what you are facing. 


          To allow ACE to start working again quick, I believe the best thing to do would be to promote the secondary server to the primary server. There are some specific steps to do this and I believe our support engineers from techsupport team would be able to assist you on this.

            • Re: ACE not working with Collective

              Hi Han,


              Thanks for the explanation. It looks more clear now. But i was wondering that if this is the case then ACE will never work on HA ? till we make secondary servers as primary server.


              Is there something OSI is coming up in future ? Apart from that , i saw that buffering is ON in the ACE server , so will all the calculation results (output tags) will automatically updated after connection ?





                • Re: ACE not working with Collective

                  Hi Prabhat,


                  Sorry for the delay in reply. Technically ACE works with HA, but with a few things that should be noted. One of the important things to take note is what I've mentioned in the previous post.


                  PRABHAT MISHRA

                  Apart from that , i saw that buffering is ON in the ACE server , so will all the calculation results (output tags) will automatically updated after connection ?

                  We configure buffering on the ACE server, such that ACE can continue to calculate and buffering data to output tags even when one of the server is down. In your setup, the expected outcome should be that the calculation continues and result sent to output tag on secondary server while buffered for the primary server. ACE would not have to be restarted.


                  I guess the problem was that the buffer wasn't working as expected, which lead to ACE being restarted when the Primary server is still down. Consequently ACE cannot start up properly because Primary server is not available.

                  • Re: ACE not working with Collective



                    PRABHAT MISHRA

                    Is there something OSI is coming up in future ?




                    An AF Analytics scheduler is being proposed as part of a future release that would also enable users to configure analytics.


                    Potentially the calculations you are running today - depending on the calculation requirements - might be able to be built using configured analytics in the future!




                    May I ask what types of calculations you are performing in ACE?


                    For example arithmetic, roll-up, specific type of analysis