Application stopped saving data


Hey guys,
I’m having some problems with my current chat application. I’m using Meteor Cluster on a MongoDB replica set with the following configuration:

“MONGO_URL”: “mongodb://myapp:mypass@mongo1:6786,mongo2:6786,mongo3:6786/myapp?replicaSet=rs0&readPreference=primaryPreferred&w=majority”

At the moment, my application doesn’t save any data anymore (two days before, it worked fine and I didn’t change anything since then). For example, if I write a message, the message is shown in my chat window, but if I reload the chat window, the message is lost. It seems to me, that there is an issue with the database. Is it possible that Meteor tries to write to a Mongo secondary? In my upstart logs, there aren’t any errors logged. Other parts of my app are also not working anymore (f.e. setting user status).

The status of my replica set is “ok”, all slaves are synced to the master.