OpenPDC - openHistorian : any 'failover' option/mechanism for the STTP connection string?

I am building an environment with the following characteristics:

  • 2 openPDC servers each receiving the same C37.118 stream as input from a third-party PDC. With a ‘share’ of the MySQL openPDC database between these two servers (using Windows DFSR), I managed to have a sort of active/active server configuration.
  • 1 openHistorian server connected to one of the two openPDC servers arbitrarily designated as ‘the primary openPDC source server’, in STTP.

I manage to manually switch the openHistorian server data feed from one openPDC server (the ‘primary’ declared server) to the other ; by changing the IP address of the source openPDC server in the concentrator device STTP connection string declared in openHistorian. I’m happy because the measurements in openHistorian stand ‘consistents’ even if the input STTP stream coming from the primary or secondary openPDC server (no duplicated measurements or loss in the data feed when switching from one to the other).

The last point I would like to improve is the manual aspect of this toggle in openHistorian’s feed. I would like to know if there is an option to perform this data source switch from one to the other of the two openPDC servers automatically; for example on the fail of openHistorian to connect to the one declared as being the primary one (server=). for example a string connection parameter like failover_server=XXX.XXX.XXX.XXX:7165

If the main server would become available again after switching to the failover one (primary server finally came back in line after a certain delay); then the connexion would automatically switch back to it …

Thank you very much for your answer.

Have a nice day,


This is already built-in, you can specify as many servers as you want using a comma, for example:


Just put them in priority order.


Hello Ritchie !

Thanks a lot for the quick reply.
I hoped that there would be a ‘hidden’ switch or a trivial trick to make it ; but did not imagine that it would already built-in and in a so simple way.

Perfect !