I’ve gotten multiple questions lately on how difficult it is to add a new node into an established AlwaysOn configuration. The answer is this – It’s easy! Let’s walk through it.
I have the original AlwaysOn replicated pair that I created a month ago and blogged about. The test servers were named DB3A and DB3B, and they formed a cluster node virtual name of DB3. We’ll add a new server called DB3C into the configuration.
First, make sure you have the cluster feature installed on the new server. If not, add it through the Server Manager, add Feature wizard.
Once the Failover Clustering services are installed, add the node. Connect to one of the two machines in the existing cluster, and open the Failover Cluster Manager. Right click on the cluster, and click Add Node.
Warnings should appear on not having shared disks. But… that’s one of the points to AlwaysOn, right? Ignore those particular errors!
You have just added the new node to the cluster! Now, remember to allow the SQL Server service able to connect to the Availability Group. Open the SQL Server Configuration Manager, right click on the SQL Server service, and hit Properties.
Restart the service to commit this change.
Now, it’s time to add this new server to the Availability Group. Open SSMS 2012 and connect to the server that is acting as the AlwaysOn Availability Group Primary server. Expand Availability Groups, and then right click on the Availability Replicas under your Availability Group. Click Add Replica.
Click Connect to load the connections to the secondary replicas. Now click Add Replica and authenticate to the third server.
All of the standard options for Availability Groups appears once authenticated. Set your options on the three tabs.
Click Next. Set a full bacukp and restore path where both service accounts have full access to, and click Next.
A validation wizard appears to check if everything is kosher before you continue.
Click to complete this operation!
The progress screen is pretty slick too!
Once this completes, make sure that everything looks good. If all is well, your screen should look similar to this.
W00t! Your third node is set up and ready to go! That wasn’t too hard, now was it?