Administration Guide : Xinet Statistics and Database Operations — the Database, Admin subtab : Enabling the database on volumes

Enabling the database on volumes
Xinet uses the usual mechanisms to deliver results of searches through its database. It first looks through the database for answers to queries, and if it doesn’t find answers there, it will then look through the file system. This will all be transparent to Xinet users. As its administrator, you may choose the Xinet volumes for which you enable the database. You may not want to turn on the database for small volumes where search speeds are already fast enough, or, for volumes without metadata, since the time your system will spend syncing volumes wouldn’t bring great improvement to the speed of your search results.
Creating a new System Volume provides actual directions for enabling the database per volume.