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How to Change Open Files Limit on OS X and macOS Sierra (10.8 - 10.12)

How to Change Open Files Limit on OS X and macOS

To check the current limits on your Mac OS X system, run in terminal:

launchctl limit maxfiles
ulimit -a

Steps

  1. Reboot the system and enter recovery mode - keep cmd (⌘) + R pressed
  2. Disable system integrity check from terminal, by typing csrutil disable
  3. Reboot
  4. Create the files below
  5. Reboot
  6. Enable system integrity check, by typing csrutil enable
  7. Reboot the system to complete the changes

The last two columns are the soft and hard limits, respectively.

Adjusting Open File Limits in Sierra

To adjust open files limits on a system-wide basis in Mac OS X Sierra, you must create two configuration files. The first is a property list (aka plist) file in /Library/LaunchDaemons/limit.maxfiles.plist that contains the following XML configuration:

sudo vi /Library/LaunchDaemons/limit.maxfiles.plist
<?xml version="1.0" encoding="UTF-8"?>  
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN"  
        "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">  
  <dict>
    <key>Label</key>
    <string>limit.maxfiles</string>
    <key>ProgramArguments</key>
    <array>
      <string>launchctl</string>
      <string>limit</string>
      <string>maxfiles</string>
      <string>64000</string>
      <string>524288</string>
    </array>
    <key>RunAtLoad</key>
    <true/>
    <key>ServiceIPC</key>
    <false/>
  </dict>
</plist> 

This will set the open files limit to 64000.

The second plist configuration file should be stored in /Library/LaunchDaemons/limit.maxproc.plist with the following contents:

sudo vi /Library/LaunchDaemons/limit.maxproc.plist
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple/DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
  <plist version="1.0">
    <dict>
      <key>Label</key>
        <string>limit.maxproc</string>
      <key>ProgramArguments</key>
        <array>
          <string>launchctl</string>
          <string>limit</string>
          <string>maxproc</string>
          <string>2048</string>
          <string>2048</string>
        </array>
      <key>RunAtLoad</key>
        <true />
      <key>ServiceIPC</key>
        <false />
    </dict>
  </plist>
  1. Change the owner for the created files
sudo chown root:wheel /Library/LaunchDaemons/limit.maxfiles.plist
sudo chown root:wheel /Library/LaunchDaemons/limit.maxproc.plist
  1. Load these new settings:
sudo launchctl load -w /Library/LaunchDaemons/limit.maxfiles.plist
sudo launchctl load -w /Library/LaunchDaemons/limit.maxproc.plist
  1. Reboot & Enable system integrity check
csrutil enable
  1. Finally, check that the limits are correct:
launchctl limit maxfiles
ulimit -a

Returned values should be the same

Both plist files must be owned by root:wheel and have permissions -rw-r--j--. This permissions should be in place by default, but you can ensure that they are in place by running sudo chmod 644 . While the steps explained above will cause system-wide open file limits to be correctly set upon restart, you can apply them manually by running launchctl limit.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>Label</key>
<string>limit.maxfiles</string>
<key>ProgramArguments</key>
<array>
<string>launchctl</string>
<string>limit</string>
<string>maxfiles</string>
<string>10240</string>
<string>12288</string>
</array>
<key>RunAtLoad</key>
<true/>
<key>ServiceIPC</key>
<false/>
</dict>
</plist>
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple/DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>Label</key>
<string>limit.maxproc</string>
<key>ProgramArguments</key>
<array>
<string>launchctl</string>
<string>limit</string>
<string>maxproc</string>
<string>2048</string>
<string>2048</string>
</array>
<key>RunAtLoad</key>
<true />
<key>ServiceIPC</key>
<false />
</dict>
</plist>
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