The Role of the Metabase in IIS

IIS operates from a copy of the metabase that is loaded into memory. When the metabase is altered, configuration changes take effect immediately in the in-memory metabase, but not in the physical metabase files.

The in-memory metabase is written to disk when one of two events occur:

  • When the IIS administration service (IIS Admin) is stopped.

  • 60 seconds after a configuration change is made unless another 30 configuration changes occurs within that 60 seconds. Each time a new configuration change is made, the timer is reset for another 60 seconds. The timer can be reset a maximum of five times before IIS forces a write to disk.

The previous copy of the metabase on disk is written to a history file when the current in-memory metabase is written to disk.

For detailed architectural and administrative information about the metabase, see the section titled IIS Metabase in the user documentation that comes with IIS.

For information about how to configure the metabase, see Comparison of IIS Administration Features and Using IIS Programmatic Administration.