Unified Automation Forum

Dear Support Team,

I am developing an OPC UA Server using you .NET Server SDK and would like to know the best way to implement transparent redundancy.

Reading through other posts, I found information that you have or are working on a C++ package to implement transparent redundancy. Is this also available for .NET?

If we have multiple OPC UA servers running behind a load balancer that balances incoming connections, would anything addition be necessary?

I assume that the session would not change between servers once established but any new connection would go to a random server. All servers share the same underlying system so all node data would be the same.

So far I looked at:
http://forum.unified-automation.com/topic611.html
http://forum.unified-automation.com/topic159.html
http://forum.unified-automation.com/topic1630.html
http://forum.unified-automation.com/topic1371.html

We estimate that our setup will have to handle approximately 100 simultaneous clients and 150,000 nodes. Each client will subscribe to only a few hundred nodes.


Sincerely,

Jonathan

I'm curious if your question regarding redundancy with the .NET server has been answered?

myoensky wrote:I'm curious if your question regarding redundancy with the .NET server has been answered?

Dear myoensky,

It has not. We currently only have one server running but may install more in the future.


Sincerely,

Jonathan

Any news in 2020 about this?

Hi,

no there are no news about the transparent redundancy in 2020. The SDK has no inbuild support for transparent redundancy (it has for non-transparent redundancy, but that was not the original question).

The loadbalancing or the clustering of multiple servers behind one single IP address is the simple part, you may get help/tools from your operating system vendor. However on the OPC UA side you must consider "sibling" connection between all redundant servers, OPC UA uses "sequence number" in all trafic, hence need to synchronize when switching over. Furthermore you should consider security (especially certificate updates) amongst your redundant servers, otherways the session will not continiously work when failover.

We have no plans to implement any "transparent redundancy" inside Unified Automation .NET SDK.
The "non-transparent redundancy" is there and can be used.