Remote tag history provider vs. remote tag provider + local history provider

Ignition
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We're preparing to launch a second gateway (for Perspective / IT) that will be connected to our current OT gateway through a gateway network. This OT gateway's default tag provider holds all the tags that drive our shop floor operations and has tag history enabled.

We plan on setting up the OT gateway as the "remote tag provider" for the incoming IT gateway, so we can read all the production tags without affecting normal operations. We want the tag historian to also move to the IT gateway. Regarding the tag historian, it sounds like we can do one of two things:

  1. Set up a local tag history provider on the new IT gateway to historize the remotely-provided tags that are coming from the OT gateway. Or...
  2. Set up a remote tag history provider on the OT gateway to historize the local OT tags using the store and forward system into the IT gateway.

Do I have this right? Is one option recommended over the other -- for example, maybe one is more performant? It seems like option 1 will do better if our main goal is to reduce load in the OT gateway, but this is all new to me so I can't be certain. All guidance is appreciated.

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  1. Use continuous DB replication from OT to IT outside Ignition, and configure the IT gateway to perform history queries with the replica.

Do not do #1--remote tag providers do not pass tag changes that happen very quickly, and you likely will not get the same historical result.

#2 is OK, but doesn't reduce load as much as #3.

3 Likes
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@pturmel, apologies for tailgating the post but it is related to:

We possibly have a project where we have 50 sites (each with 1k tags) and one central Ignition gateway where the historian will also reside. I was thinking of adding all the sites as remote tag providers to the central gateway (they have a strong VPN network across sites). Then create 50k reference tags on the central gateway and historize them on the central historian. This will allow us to only have one historian license. I am just concerned about the off chance that the VPN does go down. Will Ignition's gatway network S&F properly send historical data through to the central historian once the VPN is restored?

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Option #2 is probably what you want, possibly with a splitter if you want efficient local access to history, too. On the central gateway, you'll have a local history provider where all of the edge remote history providers send their content. Then, also on the central gateway, configure all of the remote tag providers that point at the edge gateways to use database mode for history (with the central gateway's central history database). S&F will work as you expect.