SQL Server 2012 - 3 SQL clustered instances - one default/ two named instances - how assign/should assign static ports for named instances

Question

We have two physical servers hosting 3 SQL 2012 clustered instances, one default instance and two named instances.
The default instance is using port 1433 and the two named instances are using dynamic port assignment.
There is discussion about assigning static port numbers to the two named clustered SQL instances.
What is considered best-practice?  For clustered named instances to have dynamic or static ports?
Are there any pitfalls to assigning a static port to a named instance that is a cluster?
Any help is greatly appreciated

Answer 1

Hi RobinMCBC,
In SQL server the default instance has a listener which listens on the fixed port which is TCP port 1433. And for the named instance the port on which the SQL server listens is random and is dynamically selected when the named instance of the SQL server
starts.
For Standalone instance of the SQL server we can change the dynamic port of the named instance to the static port by using SQL server configuration manager as other post, however, in case of the cluster, when we change the port no. of the named instance
to the static port using the method described above, the port no. again changes back to the dynamic port after you restart the services. I recommend you changing the Dynamic port of the SQL Server to static port 
on all the nodes , disabling and enabling the checkpointing to the quorum.
For more information, you can review the following article about how to change the dynamic port of the SQL Server named instance to an static port in a SQL Server 2005 cluster.
http://blogs.msdn.com/b/sqlserverfaq/archive/2008/06/02/how-to-change-the-dynamic-port-of-the-sql-server-named-instance-to-an-static-port-in-a-sql-server-2005-cluster.aspx
Regards,
Sofiya Li
Sofiya Li
TechNet Community Support