The following chain of events was undesireable in a redundant system.
Goal: Upgrade license with a new module on a redundant system. Version 7.5.2(b1146). The system is not connected to the internet.
Step one-- recommended by tech support. Unactivate license on master.
Step 2 through completion-- Follow the upload/download file process to upgrade the license.
Immediately after unactivating the license on the master gateway, all of the clients switch to the “trial expired” yellow screen. Upon resetting the master trial timer, the clients do not start working automatically. The application must be closed and reopened on each client.
Especially in a redundant system, it seems that the client would do whatever possible to keep running including failing over to the backup (which is still licensed) and automatically rehoming and running on the primary once it is available.
Yes, there are probably a few things we should improve in regards to upgrading the license & the actual software with redundancy.
In this case, the best thing would probably be to have the demo period automatically reset on unactivation, so that at least you could keep running unaffected for two hours.
Next, we’ve intended for a while to put a link in the master gateway that would let you transition the responsibility to the backup, triggering all clients to move over, until the master was restarted (or requested it back, if using manual recovery mode). This would let you transfer them over, so that you could upgrade the master first.
Your idea that the clients should transfer on demo expired makes sense, but would be a bit tricky. Hopefully these two updates I’ve just mentioned would be sufficient. Both would be put into the 7.5 line.
A forced failover would help a lot with Ignition’s redundancy which is one of it’s weakest attributes compared to other software.
Citect has one of the best IMHO. It fails over in a couple of seconds and clients do not see any loss of data. There is a lag in data but it gives the impression of perfection to the end user rather than the data all turning red. When you are talking a few seconds, appearance is the most important.