To sync your database you will need to move the MAMP db folder to OneDrive and then create a symbolic link in the MAMP folder back to the db folder in the OneDrive. Before starting make sure your MAMP servers are turned off, then open up terminal and enter:
cd ~/OneDrive/ cp -r /Applications/MAMP/db MAMP_DB rm -rf /Applications/MAMP/db
This will change the directory to your OneDrive folder, then copy the MAMP db folder to OneDrive and remove it from the MAMP directory. Then we have to setup the symbolic link.
ln -s ~/OneDrive/MAMP_DB/ /Applications/MAMP/db
Thats it! Now you can simply run MAPM. Use this guide to configure your second synced PC with cloud and happy coding!
Now with the new 4.4 and greater version of MAMP, you can save and load your database and document root on Dropbox (as a backup working from one computer or as a multi-working space from two computers) directly our of the box in its application.