MongoDB Installation on Mac OS X

I wanted to learn NoSQL database and so I tried to install MongoDB and learn it. However, before I could start learning, I had to learn how to install it correctly! So I have tried to write down and share whatever I faced while trying to install MongoDB.

This document applies to following:

OS X Version: 10.8.4

MongoDB version: 2.4.6

HomeBrew version: 0.9.4

To install MongoDB on Mac, I used HomeBrew package manager. I read reviews of HomeBrew and like it so chose to install it. However, you could be using MacPorts or Fink.

To install HomeBrew Package Manager, type in following on Terminal:

ruby -e "$(curl -fsSL"

Once installed, run following to make sure nothing else needs to be downloaded.

$ brew doctor

Then update and upgrade.

$ brew update
$ brew upgrade mongodb

Then you can do either of the following:

To have launchd start mongodb at login:

$ sudo ln -sfv /usr/local/opt/mongodb/*.plist ~/Library/LaunchAgents

Then to load mongodb now:

$ sudo launchctl load ~/Library/LaunchAgents/homebrew.mxcl.mongodb.plist

Or, if you don’t want/need launchctl, you can just run:

$ sudo mongod

If you are lucky(!!), like me, then you will see following when you try to run using ‘mongod’ or ‘mongo’ command respectively.

MongoDB shell version: 2.4.6
connecting to: test
Tue Sep 3 14:28:06.411 Error: couldn't connect to server at src/mongo/shell/mongo.js:145
exception: connect failed


ERROR: could not read from config file

After spending lots of time looking for solutions online, I have found a way. There are many steps which are not mentioned in the installation manual on MongoDB website. If you are stuck just like me, then follow the following steps:

  1. Update your $PATH variable to point to your MongoDB bin file. In my case brew install MongoDB to this folder:
  2. In order to update your $PATH variable, do following:
    $ sudo vi /etc/paths

    Then, press ‘i’ to insert text in Vi and append the your MongoDB path to the end of the ‘paths’ file and restart the terminal.


    Use ‘Esc : w q’ to save and exit from Vi editor.

  3. Use echo to display your path variable:
    $ echo $PATH
  4. Now try to check the Mongo version, if you get following, then you are on the right track!
    $ mongo --version
    MongoDB shell version: 2.4.6
  5. Now we need to create the database directory. I used the default ‘/data/db’ location suggested in MongoDB docs. I also created a log directory to avoid any permission issues while Mongo tries to create any logs. Change ownership and that will do the job.
    $ sudo mkdir /data/db
    $ sudo mkdir /data/log
    $ whoami
    $ chown -R username /data
  6. Now, we will create a default config file for MongoDB to be provided for the first time we run ‘mongod’ command. Now, I will also like to point out that ‘mongod’ will start a service, which will listen for incoming data connections. This is similar having ‘$service mysqld start’ executed.Let’s go ahead and create the config file. Please keep in mind that I have created very basic config file. However, you can add many other variables to configure MongoDB. This is the first time I am playing with MongoDB, so I just know as much as I read on MongoDB docs!I created ‘mongodb.conf’.
    $ sudo vi /etc/mongodb.conf

    Add following:

    fork = true
    port = 27017
    quiet = true
    dbpath = /data/db
    logpath = /data/log/mongod.log
    logappend = true
    journal = true

    Please note that the default port for MongoDB server is 27017. Use your own path for dbpath and logpath you created in Step – 5. Don’t forget to close and save the conf file.

  7. Now we are all set to start our MongoDB service. Open two instances of Terminal.In Terminal 1, type in:
    $ sudo mongod -f /etc/mongodb.conf
    about to fork child process, waiting until server is ready for connections.
    forked process: 3516
    all output going to: /data/log/mongod.log
    child process started successfully, parent exiting

    If you get above message, then know that you have successfully started your Mongod service.

    Now, to connect to it, in Terminal 2 type following:

    $mongo test
    MongoDB shell version: 2.4.6
    connecting to: test
    Server has startup warnings:
    Tue Sep 3 16:55:43.527 [initandlisten]
    Tue Sep 3 16:55:43.527 [initandlisten] ** WARNING: soft rlimits too low. Number of files is 256, should be at least 1000

    Ignore the warnings, but you are successfully connected to the ‘test’ database! Cool!

    Do a small test like below:

    > { a: 1 } )
    > db.test.find()
    { "_id" : ObjectId("522588b9d283d1fb90a43c17"), "a" : 1 }

    Congratulations! You just added a key-value pair in your ‘test’ database and retrieved it!

Alright, so this was my experience installing and running MongoDB and HomeBrew on my Mac. I hope you guys will find it helpful.

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