“Too many open files” limit/ulimit on Mac OS X

Ran into this often enough that I just wanted to summarize the steps I took based on this post to permanently increase the limit of number of open files on my Mac.

Before I started (and after getting the error):

$ ulimit -a
[...]
open files                      (-n) 256
[...]
max user processes              (-u) 709
[...]

Steps To Fix

• Become root (let’s not argue right now …): $ sudo su — root
• Create /Library/LaunchDaemons/limit.maxfiles.plist with this content; file will (must) be owned by root, which is important:

<?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>524288</string>
      <string>524288</string>
    </array>
    <key>RunAtLoad</key>
    <true/>
    <key>ServiceIPC</key>
    <false/>
  </dict>
</plist>

• If you also want the number of allowed processes increased, create
  /Library/LaunchDaemons/limit.maxproc.plist with content:

<?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>

• Restart your computer!

After:

$ ulimit -a
[...]
open files                      (-n) 524288
[...]
max user processes              (-u) 2048
[...]