Question: how to disable xdb in sitecore 9?
Answer: Open the Sitecore. Xdb. ... 
Locate the Xdb. Enabled setting. ... 
Set the value of the value attribute to false . <setting name="Xdb.Enabled" value="false" />
Locate the Xdb. Tracking. ... 
Set the value of the value attribute to false . ... 
Save the file.