I have a client running 9.3 OnPrem. They set up availability group (AG) listeners for their SQL servers and included the xConnect collection databases in the group. The Shards are in the AG, and it appears to be quite upsetting for the application. The logs are filled with the error below, and (we think) it is causing some performance impacts to page loads. There is also functionality that depends on xConnect that does not appear to be working due to the database errors.
I have a member of our Managed Services team telling me that the Shards should not be added to an AG, as it tends to be redundant (overkill) and a waste of performance. I'm wondering if this is the case, and what sort of alternatives there are for HA/DR strategies if the Shards cannot be replicated.
2020-04-10 12:12:28.429 -05:00 [Error] The target database, 'sc_Xdb.Collection.Shard0', is participating in an availability group and is currently not accessible for queries. Either data movement is suspended or the availability replica is not enabled for read access. To allow read-only access to this and other databases in the availability group, enable read access to one or more secondary availability replicas in the group. For more information, see the ALTER AVAILABILITY GROUP statement in SQL Server Books Online.