Why?
Mongoose 2.0 has different methods for connecting to replicaSets
// for single connectionsmongoose.connect()mongoose.createConnection// for replicaSetsmongoose.connectSet()mongoose.createSetConnection()
This is lame, and is lucky fixed in 3.0, but if you aren't quite there yet, this does the work for you, assuming your connection strings are comma delimted
Example
var mongoose = require("mongoose")var mongooseConnector = require("mongoose-connector")var singleDb = "mongodb://localhost:27017/test"var replicaDb = "mongodb://hostone:27017/test,mongodb://hosttwo:27017/test"// singleDb connectvar db = mongooseConnector(mongoose, singleDb)var dbReplica = mongooseConnector(mongoose, replicaDb)