Database-driven sessions offer potentially better security since the session information is not stored on the file system.
ProcessWire comes with the option to use database-driven sessions, but it is not turned on by default. However, in a shared environment, database-driven sessions offer potentially better security since the session information is not stored on the file system.
To enable database-driven sessions, login to your admin and go to Modules > Core > Session > Session Handler Database. Click the Install button. Database-driven sessions will be enabled immediately, which means you are immediately logged out. Simply log back in, and your system is now using database-driven sessions.
As a bonus, you can now monitor live traffic on your site from Setup > Sessions. If you want the information present on this screen to include IP address and/or user agent, enable these options from the Session Handler Database module configuration screen.