Upgrade procedure in load balanced environment

1. Backup the production environment and database.
2. Deploy the code and the database to your test environment and upgrade them using the Upgrade procedure.
3. Test the upgrade.
4. On the live environment, disconnect one node from the load balancer.
5. In the connection string of the other nodes, set IgnoreDowngradeExceptions property to true.
   For more information, see Upgrades and database.
   

   EXAMPLE: <add connectionString="data source=.\SQL2014;Integrated Security=SSPI;initial catalog=Database" name="Sitefinity" IgnoreDowngradeExceptions="true" />

6. Upload the upgraded source code to the disconnected node.
   Make sure that its IgnoreDowngradeExceptions property to false.
   This will upgrade the database, shared by all nodes. The rest of the nodes will operate with the upgraded database because of the IgnoreDowngradeExceptions parameter is set to true.
7. Warmup the node, run precompilation and any tooling specific to your site needs to prepare this node to serve visitors.
   Once this completes, attach this node to the load balancer.
8. Repeat the same procedure with all the other nodes.
   After you disconnect a node and upload the upgraded source code, set its IgnoreDowngradeExceptions parameter to false.
   

1. Backup the production environment and database.
2. Deploy the code and the database to your test environment and upgrade them using the Upgrade procedure.
3. Test the upgrade.
4. On the live environment, disconnect one node from the load balancer.
5. Deploy the upgraded source code and restore a copy of the upgraded database.
6. Switch the site traffic to this node.
7. Deploy the upgraded source code to the rest of the nodes and make them point to the upgraded database of the first node.
8. Attach back the nodes to the load balancer.

LIMITATIONS: There is a data loss at the time between taking database backup to upgrade the site. To limit the data loss take a backup right after the upgraded Sitefinity project files have been uploaded to one of the nodes and the upgrade process have been tested in a test environment to execute without issues.