We had a problem with a SharePoint implementation recently. All of a sudden, document icons were missing from document libraries, the New... button did not work, the option "Edit with Microsoft Word" was missing, and so on...

The reason for all of this? Incorrect permissions on docicon.xml on the web front-end server. That file contains definitions of file types, their icon and how these files should be opened. Make sure that the file inherits its permissions from the parent. If only Administrators and SYSTEM have rights, it will not work (obviously).

On the Microsoft SharePoint Products and Technologies Team Blog, Troy Starr is writing a series of blog posts about alternate access mappings (AAM). AAM is something particularly tricky in a SharePoint deployment that you need to get right. Depending on the complexity of your configuration (intranet, extranet, SSL, ...) you need to configure AAM appropriately.

Check out part 1 and part 2. Part 3 is coming later.

Microsoft released a new white paper about database mirroring with MOSS 2007 and WSS v3.0. The key point is that you need to perform some actions when a failover happens. You can do these actions manually or implement them using some scripts. You will also have to do some monitoring to know when a failover has happened.

If you are planning to use database mirroring with SharePoint, all I can say is test, test, test!!!