@WhereMatters
I just re-read my post and realise I have misled you.
In our large AWS hosted HA Enterprise site, we don't use FSx for ArcGIS Server Config files, only for the Server Directories (and Portal Content).
We do use DynamoDB for the AGS Config - and for the very reason you suggested - to ensure millisecond read-write consistency. When publishing, it is important to ensure the updates to config tables happen rapidly as there are a few individual service requests that are managed at this time, and any inconsistency may cause corruption. DynamoDB provides this fast update, we can't be certain that FSx will do so.
so, to summarise, FSx good for the Server Directories (arcgiscache, arcgisoutput, arcgissystem).
- and for file based registered data stores.
But DynamoDB is the best HA solution for the AGS Configuration.
FSx can also be used for Portal Content, but it is cheaper to use S3 for this.
sorry if I have caused any confusion.