Since the release of AppSense Environment Manager 8.0.983.0 AppSense have supported Microsoft SQL Mirroring to provide high availability.
The following diagram provides a high level view on what the infrastructure is likely to look like:
The infrastructure above would protect the customer from a database failure where all IIS Servers would fail over to the database in Datacentre 2 in the event that the database server in Datacentre 1 went down automatically.
This is done through a simple modification to the web.config and the backgroundservice.exe.config file by adding a failover partner as described within the AppSense Environment Manager Personalization Server Product Guide:
The beauty of this design is that it is simple... It won't take you long to configure the servers, database and configure replication and once its up and running it will work well. The only caveats I must add are that switching mirroring on requires you to set the database to FULL RECOVERY which will cause the transaction log to grow however in a production environment you would be taking regular SQL backups so this shouldn't be an issue.
Thanks for reading,