Welcome back to squirrel’s blog on “everything” SQL Server. I will be covering little nuances with Database Mirroring here. Database Mirroring is a very cool feature in SQL Server 2005 when you get it setup and configured properly. I went through the growing pains of installing, configuring and troubleshooting this process.
Before I installed it on my production database servers I used an application called VM Workstation – http://www.vmware.com. With this cool software I was able to create the production SQL Servers (here you will need the Windows and SQL Server ISOs) but in a virtual form. My production database servers have Windows 2003 Server and SQL Server 2005. Once I got 3 (Principal server, Witness server, Mirror server) virtual machinesservers setup I went ahead and installed and configured Database Mirroring. Import thing to note… you will need to install SQL Server 2005 Service Pack 1 or later for database mirroring to work. Database Mirroring is disabled by default.
When setting up the servers to participate in the mirroring process it is import to fully qualify the server name e.g. mycompname.mydomainname in order for Database Mirroring to see the servers. I tried it using the IP Addresses but Database Mirroring did not like that. Also, fortunate for me all of my servers were in the same domain. If anyone has experience going across different domains please share your experience. Last thing to note on Database Mirroring… when using a Witness server if there is a ‘hick up’ in the network the Witness will view that as a failure in the communication between the Principal and Mirror servers and will automatically “fail” it over to the mirror server. For this reason, I have left the Witness server out of the configuration and just have the Principal server and the Mirror server. If there is a production problem then you can fail it over manually.
For more information on Database Mirroring please see BOL.