Nodemon Error: “System limit for number of file watchers reached”

You need to increase the inotify watchers limit for users of your system. You can do this from the command line with:

sudo sysctl -w fs.inotify.max_user_watches=100000

That will persist only until you reboot, though. To make this permanent, add a file named /etc/sysctl.d/10-user-watches.conf with the following contents:

fs.inotify.max_user_watches = 100000

After making the above (or any other) change, you can reload the settings from all sysctl configuration files in /etc with sudo sysctl --system. (On older systems you may need to use sudo sysctl -p instead.)

I sometimes get this issue when working with Visual Studio Code on my Ubuntu machine.

In my case the following workaround helps:

Stop the watcher, close Visual Studio Code, start the watcher, and open Visual Studio Code again.

In order to test the changes, I temporary set the parameter with the value 524288.

sysctl -w fs.inotify.max_user_watches=524288

Then I proceed to validate:

npm run serve

And the problem was solved. In order to make it permanent, you should try to add a line in the file “/etc/sysctl.conf” and then restart the sysctl service:

cat /etc/sysctl.conf | tail -n 2
fs.inotify.max_user_watches=524288

sudo systemctl restart systemd-sysctl.service

I had the same problem. However, mine was coming from Webpack. Thankfully, they had a great solution on their site:

For some systems, watching many files can result in a lot of CPU or memory usage. It is possible to exclude a huge folder like node_modules using a regular expression:

File webpack.config.js

module.exports = {
  watchOptions: {
    ignored: /node_modules/
  }
};

This is a problem of inotify (inode notify) in the Linux kernel, so you can resolve it by using this command:

1. For a temporary solution until rebooting the pc, use the following command

   sudo sysctl -w fs.inotify.max_user_watches=100000
   

2. A permanent solution: To make this permanent, add a file named /etc/sysctl.d/10-user-watches.conf with the following contents:

   fs.inotify.max_user_watches = 10000
   

After making the change, reload the settings from all sysctl configuration files in /etc with sudo sysctl -p.

adasdas

It can be hard to know how much to increase the number of watchers by. So, here’s a utility to double the number of watchers:

function get_inode_watcher_count() {
  find /proc/*/fd -user "$USER" -lname anon_inode:inotify -printf '%hinfo/%fn' 2>/dev/null | 
  xargs cat | 
  grep -c '^inotify'
}

function set_inode_watchers() {
  sudo sysctl -w fs.inotify.max_user_watches="$1"
}

function double_inode_watchers() {
  watcher_count="$(get_inode_watcher_count)"
  set_inode_watchers "$((watcher_count * 2))"

  if test "$1" = "-p" || test "$1" = "--persist"; then
    echo "fs.inotify.max_user_watches = $((watcher_count * 2))" > /etc/sysctl.d/10-user-watches.conf
  fi
}

# Usage
double_inode_watchers
# to make the change persistent
double_inode_watchers --persist

In my case, while I’m doing the nodemon command on the Linux server, I have my Visual Studio Code open (SSH to the server). So based on Juri Sinitson’s answer, I just close Visual Studio Code and run the nodemon command again. And it works.

My nodemon command:

nodemon server.js via npm start

I think most answers given here are correct, but using the systemctl command to restart my service solved the problem for me. Check the command below:

sudo systemctl restart systemd-sysctl.service

You should follow answers such as this one:

cjs’

Or:

Isac Moura’s

And for latest Ubuntu versions, run sudo sysctl --system to read these settings anew.

However, in my case, my changes to these configuration files were not picked up, because I had already tweaked these settings a while ago… and forgot about it. And I had placed the conflicting configuration file in the wrong place.

According to man sysctl.d, these settings can be placed in /etc/sysctl.d/*.conf, /run/sysctl.d/*.conf and /usr/lib/sysctl.d/*.conf.

In my case I had two files:

/etc/sysctl.d/10-user-watches.conf
/usr/lib/sysctl.d/30-tracker.conf     <<< Older file, with lower limit

Due to the naming convention, my older file was read last, and took precedence.