MongoDB secondary replica does not have collections as in primary

Question

I have set up a mongodb replica set on my local machine, and created couple of collections in a database named "adaptive-db". From the mongo shell, when i connect to the primary and run show dbs, i can see and query my database "adaptive-db".

I then switched to secondary, and ran rs.slaveOk() expecting to see the "adaptive-db" created in primary to be present in secondary as well, but i don't see it.

Here are the commands i ran:

shell:bin user1$ ./mongo localhost:27017
MongoDB shell version: 3.0.2
connecting to: localhost:27017/test
rs0:PRIMARY> show dbs
adaptive-db  0.125GB
local        0.281GB
rs0:PRIMARY> use adaptive-db
switched to db adaptive-db
rs0:PRIMARY> show collections
people
student
system.indexes
rs0:PRIMARY> db.people.find().count()
6003
rs0:PRIMARY> exit
bye


shell:bin user1$ ./mongo localhost:27018
MongoDB shell version: 3.0.2
connecting to: localhost:27018/test
rs0:SECONDARY> show dbs
2015-06-25T11:16:40.751-0400 E QUERY    Error: listDatabases failed:{ "note" : "from execCommand", "ok" : 0, "errmsg" : "not master" }
    at Error (<anonymous>)
    at Mongo.getDBs (src/mongo/shell/mongo.js:47:15)
    at shellHelper.show (src/mongo/shell/utils.js:630:33)
    at shellHelper (src/mongo/shell/utils.js:524:36)
    at (shellhelp2):1:1 at src/mongo/shell/mongo.js:47
rs0:SECONDARY> rs.slaveOk()
rs0:SECONDARY> show dbs
admin  0.031GB
local  0.281GB
rs0:SECONDARY> 

Can someone plz explain me why? Here is my rs.conf():

rs0:SECONDARY> rs.conf()
{
    "_id" : "rs0",
    "version" : 7,
    "members" : [
        {
            "_id" : 0,
            "host" : "localhost:27017",
            "arbiterOnly" : false,
            "buildIndexes" : true,
            "hidden" : false,
            "priority" : 1,
            "tags" : {

            },
            "slaveDelay" : 0,
            "votes" : 1
        },
        {
            "_id" : 1,
            "host" : "localhost:27018",
            "arbiterOnly" : false,
            "buildIndexes" : true,
            "hidden" : false,
            "priority" : 1,
            "tags" : {

            },
            "slaveDelay" : 0,
            "votes" : 1
        },
        {
            "_id" : 2,
            "host" : "localhost:27019",
            "arbiterOnly" : false,
            "buildIndexes" : true,
            "hidden" : false,
            "priority" : 1,
            "tags" : {

            },
            "slaveDelay" : 0,
            "votes" : 1
        }
    ],
    "settings" : {
        "chainingAllowed" : true,
        "heartbeatTimeoutSecs" : 10,
        "getLastErrorModes" : {

        },
        "getLastErrorDefaults" : {
            "w" : 1,
            "wtimeout" : 0
        }
    }
}

Thanks

Answer 1

I'm guessing a little, but judging by other collections you see, you are in the local database. Which, as the name suggests is not replicated (it contains oplog, startup_log and other things like that, which are specific to instance and would get messed up if replicated).

Use a different database. Either connect to 127.0.0.1/somedb (use appropriate IP/hostname), or do use somedb, to switch databases while in console. Then create collections and those should get replicated (to the database of same name, of course - somedb in my example).

Answer 2

For newer version of MongoDB run the command rs.secondaryOk() on the secondary database.

Answer 3

Run the command rs.slaveOk() on the secondary replica member; this allows the current connection to allow read operations to run on the secondary member.

For reference: http://docs.mongodb.org/manual/reference/method/rs.slaveOk/