This "main point" is never mentioned in their philosophy page. And the introduction mentions "Optional streaming writes (no acknowledgements)" which sounds like

This "main point" is never mentioned in their philosophy page. And the introduction mentions "Optional streaming writes (no acknowledgements)" which sounds like the default is synchronous writes. http://www.mongodb.org/display/DOCS/Philosophy http://www.mongodb.org/display/DOCS/Philosophy I admit that the default unsafe tuning of MongoDB becomes quite obvious when you read more of the manual, but I can hardly say 10gen is without blame for causing this confusion.