Running Ignition 8.1.25 with redundancy enabled. Both servers are headless linux.
Redundancy is cold & partial.
I have a myriad of devices connected (~60), most are modbus, with a half dozen DNP3.
When I perform a failover, the backup server does not successfully connect to any devices. The connected devices list would indicate they are connected, but inspecting the connections device side, there are no packets being sent (modbus) or packets slow to a crawl at 1 in 5sec (DNP3), which without history is as good as disconnected anyway and the data turns stale/bad.
The log on the backup is filled with SocketIODelegate faults, for example:
java.io.IOException: End of stream reached.
at com.inductiveautomation.iosession.socket.AsyncSocketIOSession.run(AsyncSocketIOSession.java:74)
at java.base/java.lang.Thread.run(Unknown Source)
I try reset the connection from the device end, but Ignition never re-initiates.
The "End of stream" tells me that this is a modbus device closing the connection, which indicates in turn that the primary never let go of it completely?
Backup server pre-fail over:
Backup server post-fail over
In opposition to the above, the device side of those modbus connections indicates disconnected and no packets are being sent. The tag browser also indicates bad data.
Edit: I should add.. if I fail 'back' and assume control on the primary.. all of the connections resume and everything is ok!
Hmmm. I can't help you with the IA driver (and I suspect you need to call support), but I'd be curious what you get if you substitute my alternate driver. Perhaps in parallel with some extra tags to not disturb your production kit.
It's a totally different code base, so if mine does the same, it probably isn't a problem inside Ignition.
Hello,
I'm having a similar issue, I have 9 modbus TCP devices connected to a Master - backup redundancy pair. When the Master fails then the backup have access to all the devices, no problem with that but... when the Master comeback then 3 of 9 devices remains disconnected in the master but still connected on the backup server!!! Then I need to disable and enable the device again to hook the device to the master server...
Any idea how to fix this?
thanks in advance!
MF
Have you tried my alternate driver? It has settings specifically for situations like this.
Make sure the "Standby Activity Level" is set to Cold.
I'm using Warm!! is that an issue?
why Warm is not usable?
thanks !
In Warm mode, devices are expected to make and keep connections on both master and backup. Sounds like you don't want that.
where can I find it?
thanks
It is linked above, in comment #2.
Here's another copy:
Hi Kevin,
I need a fast switchover from Mater to backup and vice versa. That's why I selected warm instead of cold mode.
but why isn't working in warm mode?
why the other 6 devices seem to be ok with the warm mode but only 3 are not working?
It sounds like these devices limited in the number of connections they can accept/maintain.
good point, thanks very much for your help!
I've a last question, how faster is Warm vs Cold mode?
I mean, practically is very different?
thanks again!
I don't know, you'll have to try it and see.
Ignition failover in any configuration isn't very fast, so I wouldn't expect much difference, but 
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