title: MongoDB replica set with write concern w:0
body: <p>I am trying to configure MongoDB on 3 nodes to provide failover in case some of the nodes are down.</p>
  
  <p>Where one node is down, the election algorithm chooses a primary and both writing and reading works. But with 2 nodes down the election is not allowed since the majority cannot be obtained; the client may read but writing fails.</p>
  
  <p>On the other hand, setting the write concern to 0 should allow writing with only one functional node (though inconsistencies may later arise).</p>
  
  <p><b>My question is, is possible to have a replica set with write concern 0 to allow writing with two nodes down?</b> It does not seem to work for me; I get a timeout exception (waiting for a server that matches WritableServerSelector).</p>