SQL Aliasing Pros and Cons

I wanted to write a quick note on the good and bad of using SQL aliasing for redirecting SharePoint between mirrored SQL nodes.

Good - It's a very simple solution. Each application server in the farm simply needs to be configured with the alias information. Ultimately, you can tweak this entry using a single registry change.

Good - No performance implications.

Bad - Since the IP of your SQL server changes, you have to recycle your sharepoint app pools to bring SharePoint online even after changing the alias entry. This is because the IP gets cached in the process.

Bad - The alias is known only to the servers where you configure it. This means that other applications that depend on connecting to the same database server by resolving the name from SharePoint will not be able to unless they also have an alias configured. This can quickly get out of control for certain situations such as having lots of farms that consume shared services from a global SSP farm.

Bad - SQL aliasing for SharePoint is not officially supported yet. I wouldn't let this hold you back, but if you have to call support, you might want to leave that detail out. Don't tell them that I said that ;-)