Exception in initandlisten: 29 data directory /data/db not found., terminating

Question

Problem :

When I was trying to run the Mongod in terminal I got below message :

2020-01-14T17:33:04.554+0700 I STORAGE  [initandlisten] exception in initAndListen: 29 Data directory /data/db not found., terminating
2020-01-14T17:33:04.554+0700 I CONTROL  [initandlisten] dbexit:  rc: 100

And after running mongo command I got below message :

MongoDB shell version: 3.0.3
connecting to: test
2020-01-14T17:34:26.679+0700 W NETWORK  Failed to connect to 127.0.0.1:27017, reason: errno:111 Connection refused
2020-01-14T17:34:26.681+0700 E QUERY    Error: couldn't connect to server 127.0.0.1:27017 (127.0.0.1), connection attempt failed
    at connect (src/mongo/shell/mongo.js:179:14)
    at (connect):1:6 at src/mongo/shell/mongo.js:179
exception: connect failed

I am using the Ubuntu 14.04 LTS 64 bit. How can I fix this issue?

Answer 1

The MongoDB needs a data directory to store data. The Default path is /data/db

When you start the MongoDB engine, it tries to search above directory which is missing in your case. So solution is to create this directory and assign the rwx permission to your user.

If you want to change your path of the data directory then you must specify it while starting the mongod server as below,

mongod --dbpath /data/<path> --port <port no> 

This will help you in starting your mongod server with your custom path and the port number.

Answer 2

The error message you are getting is “Unable to create lock file: /data/db/mongod.lock errno: 13 Permission denied. The directory you are creating does not seem to have the correct permission and ownership. This required to be writeable by the users who run on the MongoDB process.

Check the permission and ownership:

To see the permission and ownership of the ‘/data/db/’ directory, that is what the permission and ownership should look like;

$ ls -ld /data/db/

drwxr-xr-x 4 mongod mongod 4096 Oct 26 10:31 /data/db/

The left side drwxr-xr-x  shows permission for users, groups, and others. Mongod mongod shows who owns the directory and which group that the directory belongs to.

Solution:

If your ‘/data/db/’ directory does not have the permission and ownership above, then do this;

First, check what user and group your mongo user has;

# grep mongo /etc/passwd

mongod:x:498:496:mongod:/var/lib/mongo:/bin/false

you must have an entry for mongod in /etc/passwd, as it is a daemon.

sudo chmod 0755 /data/db

sudo chown -R 498:496 /data/db    # using the user-id , group-id

The user can also use the user-name and group-name as follows;

sudo chown -R mongod:mongod /data/db

That should make it work.

In the comments below, some people use this;

sudo chown -R $USER /data/db

sudo chmod -R go+w /data/db

The disadvantage is that the $USER is an account that has a login shell. Daemons ideally have not the shell for the security reasons, that’s why you see in the grep of the password file.