title: How to keep global variables persistent over multiple google appengine instances?
body: <p>Our situation is as follows:
  We are working on a schoolproject where the intention is that multiple teams walk around in a city with smarthphones and play a city game while walking.
  As such, we can have 10 active smarthpones walking around in the city, all posting their location, and requesting data from the google appengine.</p>
  
  <p>Someone is behind a webbrowser,watching all these teams walk around, and sending them messages etc.</p>
  
  <p>We are using the datastore the google appengine provides to store all the data these teams send and request, to store the messages and retrieve them etc.
  However we soon found out we where at our max limit of reads and writes, so we searched for a solution to be able to retrieve periodic updates(which cost the most reads and writes) without using any of the limited resources google provides. And obviously, because it's a schoolproject we don't want to pay for more reads and writes.</p>
  
  <p>Storing this information in global variables seemed an easy and quick solution, which it was... but when we started to truly test we noticed some of our data was missing and then reappearing. Which turned out to be because there where so many requests being done to the cloud that a new instance was made, and instances don't keep these global variables persistent.</p>
  
  <p>So our question is:
  Can we somehow make sure these global variables are always the same on every running instance of google appengine.
  OR
  Can we limit the amount of instances ever running, no matter how many requests are done to '1'.
  OR
  Is there perhaps another way to store this data in a better way, without using the datastore and without using globals. </p>