# Ignition OPC UA Server Redundancy (Modbus TCP) **URL:** \ **Category:** Ignition\ **Tags:** redundancy\ **Created:** [December 1, 2022, 7:49am UTC](https://forum.inductiveautomation.com/t/ignition-opc-ua-server-redundancy-modbus-tcp/67123 "2022-12-01T07:49:00Z")\ **Posts on this page:** 1\ **Showing post:** 10
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [July 12, 2023, 4:23pm UTC](https://forum.inductiveautomation.com/t/ignition-opc-ua-server-redundancy-modbus-tcp/67123/10 "2023-07-12T16:23:12Z")
It wasn't quite as easy as the last change, but relatively easy. _ **Utterly untested** _, feedback welcome: **BETA** for Ignition 8.1: ~~v1.1.4.231931604~~ Some notes: - When active, the driver alternates between the live connections on a per-batch basis. For this driver, a "batch" is a memory area subset of a single `system.opc.readValues()` request, `system.opc.writeValues()` request, or subscription poll. (Coils with coils, discrete inputs with discretes, et cetera.) This is effectively load-balancing between the connections, though not deliberately so. (Batch sizes vary and are not considered in the toggling.) - When a single connection breakage occurs, the batches that were queued to the now-broken connection will fail. For subscriptions, bad quality will appear for one subscription cycle. Non-subscription reads and any writes should be monitored for error results and retried. - Only available for Modbus TCP, not any form of RTU. - Device status will include "Degraded" or "Recovering" if the two connection states differ. I probably won't have a chance to properly test this until next week. I thought y'all might like this preview. --- _[View the full topic](https://forum.inductiveautomation.com/t/ignition-opc-ua-server-redundancy-modbus-tcp/67123)._