Read-only file system when attempting mkdir /data/db on Mac [closed]

Question

If you have Mac and updated to Catalina than the root folder is no longer writable.

I just changed the directory somewhere else.

Been using this command for now

mongod --dbpath=/Users/user/data/db

from the official docs https://docs.mongodb.com/manual/tutorial/install-mongodb-on-os-x/

install homebrew and run the following commands

sudo chown -R $(whoami) $(brew --prefix)/*

then

brew tap mongodb/brew

then

brew install [email protected]

and

brew services start mongodb-community

or

mongod --config /usr/local/etc/mongod.conf

then

ps aux | grep -v grep | grep mongod

and

mongo

to verify you can run show dbs in the mongo shell

With the new macOS Catalina update, the folder /data/db becomes read-only, you cannot modify it. Follow this procedure to create a DB in another folder:

1. Change mongod directory :

   sudo mongod --dbpath /System/Volumes/Data/data/db

2. Give it an alias to use it as mongod:

   alias mongod="sudo mongod --dbpath /System/Volumes/Data/data/db"

3. Just type mongod in your terminal, it should work.

Extra => If you need to give it current user rights, use this line of code :

sudo chown -R $(whoami) /System/Volumes/Data/data/db

(Just for info -> $(whoami) is just a variable that returns your current user)

To make a permanent change of the path of mongod db folder.

Following these docs they say roughly this. If mongod is started with brew services:

$ brew services start [email protected]

It will use config file at path /usr/local/etc/mongod.conf

---

To fix this, edit the config file:

$ vim /usr/local/etc/mongod.conf

And change the dbPath e.g. to your home directory like this:

systemLog:
  destination: file
  path: /usr/local/var/log/mongodb/mongo.log
  logAppend: true
storage:
  dbPath: /Users/<username>/data/db
net:
  bindIp: 127.0.0.1 

Save the file and restart mongod with brew:

$ brew services restart [email protected]

You can't create a folder on the root directory on Mac Catalina anymore!

https://www.apple.com/macos/catalina/features/

Dedicated system volume

macOS Catalina runs in a dedicated, read-only system volume — which means it is completely separate from all other data and helps improve the reliability of macOS.

# macOS Catalina, mkdir path
$ sudo mkdir -p /System/Volumes/Data/data/db

# give permissions
$ sudo chown -R `id -un` /System/Volumes/Data/data/db

# macOS 10.14.x -
$ sudo mkdir -p /data/db

# macOS 10.15.x +
$ sudo mkdir -p /System/Volumes/Data/data/db

refs

https://discussions.apple.com/thread/250720711

https://zellwk.com/blog/install-mongodb/

https://www.youtube.com/watch?v=DX15WbKidXY

So, with macOS Catalina Apple created a new Volume for security purposes. If you’re on macOS Catalina, you'll need to create the /data/db folder in System/Volumes/Data.

Follow these commands

1. sudo mkdir -p /System/Volumes/Data/data/db
2. sudo chown -R id -un /System/Volumes/Data/data/db

Start MongoDB

3. brew services run mongodb-community

4. Enjoy 😉