MongoDB Replication for Backup

Question

Our's is a small application. Every day we do mongodump and take DB backup to Amazon Glacier. Instead of this I would like to use MongoDB replication that will copy actual database on another different server. So that on failure of main server There will be no actual data loss.

I don't want secondary server to take over automatically which we can handle manually later. But the goal is to have the latest data ready on another server.

Answer 1

You could create a ReplicaSet and configure the second server as delayed hidden member. Could be like this:

rs.initiate(
   {
      _id: "myReplSet",
      members: [
         { _id: 0, host : "mongodb0.example.net:27017" },
         { 
            _id: 1, 
            host : "mongodb1.example.net:27017", 
            hidden: true, 
            priority: 0, 
            votes: 0, 
            secondaryDelaySecs: 60 * 30
         }        
      ]
   }
)

Such member will hold a copy of the primary data with a delay of 30 Minutes. You cannot run any CRUD operations on it and it never becomes the PRIMARY.

I would suggest a delayed member, because if one does a bad command by accident, (e.g. drop collection) then you have half an hour to shutdown the database. Then you can restore from secondary.

MongoDB Document on Hidden Replica Set Members