RE: The Migration Checklist – SQLServerCentral

SSC-Forever

Points: 42192

March 9, 2017 at 7:26 am

#1932506

Stefan LG - Wednesday, March 8, 2017 2:16 AM
...When you mention "side-by-side" migration I assume you are using the same host name for the new server and SQL Server instance?
For me, this has been the biggest challenge in these type of migrations before.
In virtual environments you can setup private networks to isolate the new server from the production network.
But sometime there are many third-party applications that must be tested before the new server can go on-line.
Some external systems also use hosts files where the IP address/host name is hard-coded...

A technique I've used over the years to handle the side-by-side same name situation, is to have an extra DNS entry that clients use to connect to instead of the physical server name itself. Then, once the new server has been setup and tested, and you're ready for cutover, it's just a matter of changing the IP address of that extra entry. Physically changing the name of the box that SQL Server is running on can work too, but I find the extra entry a bit more elegant.

I've only worked at one place that clients connected to the SQL Servers by IP address, and while that was only 7 years ago it seemed so... 1990's. I remember we created Aliases on the clients in SQL Server Configuration Manager to help deal with that situation.