title: What approaches are available to insert and basically synchronize data between scaled databases?
body: <p>I'm thinking about what approaches can developer take to insert or synchronize data between multiple dbs, which are a replicas of each other? </p>
  
  <p>I know that there might be a Server, which is located before the serveral instances of for example MySQL, and it can just replicate the data to each other, and it can notify application about the status in form of status. For example Green means that data is available everywhere, yellow means that it is available only on few instances and replication is in progress. Red means an error.
  Other approach would be to have such server in front of those db instances, but in this case each db stores a range of keys of data. In such situation that server would have some kind on algorithm which will determine to which db it should put the data.</p>
  
  <p>I think that replication is not good enough. Can you suggest better approach?
  The later scenario is weak in my opinion because there is a bigger danger of loosing data (if db with its own replicas will die).</p>