Dear, Ignition Scale Out Architecture with Redundancy，how to configure，is there a configuration document ?
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Don't forget there is an Internet...
Are you going to have redundant backend, frontends and historians?
Basically in the past we have created separate redundant backend gateways that are only I/O. Then redundant front ends for vision. The backend gateways end up being a remote tag provider for the front ends.
Historians is a bit more tricky but same concept. On the backend server they will communicate with the historians as remote history providers.
I reccomend EAM for management, updates etc...
If you have any specific questions please don't hesitate to ask.
How to configure? backend and frontend.
And,for redundant , backend or frontend need have same project?
The first sentence of the user manual page linked by @jlandwerlen:
Ignition redundancy supports a 2-node system, meaning there are two copies of the Gateway running. One node is the Master Gateway and the other is the Backup Gateway or backup node. All projects, Gateway settings, etc., are shared between nodes. The master node manages the configuration then replicates it to the backup node.
The exact role a particular Ignition gateway takes is entirely up to you. There are no predefined roles in the software (apart from master and backup for redundancy). You can use remote tag providers to split up the execution of tags from visualization, which is most common, but Ignition is flexible and does not proscribe a single particular pattern.
You will probably find a conversation with our Sales or Sales Engineering team(s) more valuable than a forum post.