There is one feature of IIS 6.0 that I have not expanded on yet and this is the Metabase.

As you know, the Metabase is where IIS stores it configuration and in IIS6.0 the Metabase is in a human readable XML format. This allows for great flexibility, as you can fire up any text editor and edit the Metabase.xml file which is stored at systemroot\System32\Inetsrv\.

The change in format of the Metabase from a binary format to an XML format is itself a very important and useful change from previous versions of IIS, but also there are some other changes that have taken place on how configuration changes can be performed, can be moved between systems and can be applied to a system.

One of the new features is that there is a backup and restore capability to the Metabase. This capability can be accessed manually from the IIS console manager, through scripts and is leveraged every time there is a change to either the Metabase.xml file and/or the schema for the XML file (i.e. MBSchema.xml ).  This gives you quite a bit of resilience/flexibility, as you can restore a Metabase configuration back to a previously known configuration, by using a configuration stored in the History folder or import a Metabase file from a previously exported configuration. Because the IIS 6.0 does not hold onto the physical Metabase.xml file, making changes to the configuration is quite easy. The Metabase.xml is copied into memory upon startup of IIS and it maintains a filesystem change notification event to detect any changes, so that this configuration is reloaded into memory.

When IIS6 is configured for edit while running, it goes through a number of steps to verify that when a  filesystem change notification has been received, that an actual change has taken place and that the file can be properly parsed and adheres to the XML schema. The IIS 6.0 Technical Reference covers this in more detail.