# Redundant Backup Setup Issue: Master and backup are incompatible due to differences between installed modules

**URL:** <https://forum.inductiveautomation.com/t/redundant-backup-setup-issue-master-and-backup-are-incompatible-due-to-differences-between-installed-modules/36823>\
**Category:** Ignition\
**Created:** [July 17, 2020, 1:38pm UTC](https://forum.inductiveautomation.com/t/redundant-backup-setup-issue-master-and-backup-are-incompatible-due-to-differences-between-installed-modules/36823 "2020-07-17T13:38:55Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![scott.stamps](https://avatars.discourse-cdn.com/v4/letter/s/ba9def/32.png) [@scott.stamps](https://forum.inductiveautomation.com/u/scott.stamps)\
**Post date:** [July 17, 2020, 1:38pm UTC](https://forum.inductiveautomation.com/t/redundant-backup-setup-issue-master-and-backup-are-incompatible-due-to-differences-between-installed-modules/36823/1 "2020-07-17T13:38:55Z")

</div>

Hello,  
I am trying to establish a redundant backup for our primary Ignition server. The issue is that I’m seeing, from the logs: “Master and backup are incompatible due to differences between installed modules”. Comparing modules (primary server vs backup server) the only difference is the Cirrus Link Opto 22 groov EPIC and SNAP PAC Driver. It is not installed on the backup server. Also, the backup server is licensed as such, so modules can’t be installed/configured there.

The question: How do we go about getting our backup/redundancy set up?

Thanks

---

<div class="post-metadata">

**Author:** ![scott.stamps](https://avatars.discourse-cdn.com/v4/letter/s/ba9def/32.png) [@scott.stamps](https://forum.inductiveautomation.com/u/scott.stamps)\
**Post date:** [July 17, 2020, 3:12pm UTC](https://forum.inductiveautomation.com/t/redundant-backup-setup-issue-master-and-backup-are-incompatible-due-to-differences-between-installed-modules/36823/2 "2020-07-17T15:12:52Z")

</div>

Removing the backup-only license allowed us to install the missing module (Cirrus Link Opto 22) on the backup instance. Once complete, we reapplied the license. The initial sync was performed, and redundancy seems to be working as expected.

---

<div class="post-metadata">

**Author:** ![mazeyrat](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/mazeyrat/32/10955_2.png) [@mazeyrat](https://forum.inductiveautomation.com/u/mazeyrat)\
**Post date:** [July 17, 2020, 4:14pm UTC](https://forum.inductiveautomation.com/t/redundant-backup-setup-issue-master-and-backup-are-incompatible-due-to-differences-between-installed-modules/36823/3 "2020-07-17T16:14:00Z")

</div>

If you use Ignition 8,  
we encounter such of issue with our third party modules.  
The fix is here:

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/2/e/2e49f929cc5460d5971095984170f803aa5e2259.png)

> [@Nightly 8.0 Changelogs - 2020](http://forum.inductiveautomation.com/t/nightly-8-0-changelogs-2020/31153/109):
>
> Nightly Changelog: 8.0.15-b20200707 Ignition Platform 16547: Add argument to system.util.invokeAsync in all scopes to set task description Added a ‘description’ argument to system.util.invokeAsynchronous, which allows you to set the description of the asynchronous thread, to view on the script diagnostics pages for your current scope. Vision 16729: Equipment Schedule: Unhelpful error if pctDone or leadTime columns in scheduled events dataset contains null values Prevented a null pointer exce…