The default ulimits specified on OS X (10.5)

mac-osxulimit

The default nofile limit for OS X user accounts seems to be about 256 file descriptors these days. I'm trying to test some software that needs a lot more connections than that open at once.

On a typical Debian box running the pam limits module, I'd edit /etc/security/limits.conf to set higher limits for the user that will be running the software, but I'm mystified where to set these limits in OS X.

Is there a GUI somewhere for it? Is there a config file somewhere for it? What's the tidiest way to change the default ulimits on OS X?

Best Answer

Under Leopard the initial process is launchd. The default ulimits of each process are inherited from launchd. For reference the default (compiled in) limits are

$ sudo launchctl limit
    cpu         unlimited      unlimited      
    filesize    unlimited      unlimited      
    data        6291456        unlimited      
    stack       8388608        67104768       
    core        0              unlimited      
    rss         unlimited      unlimited      
    memlock     unlimited      unlimited      
    maxproc     266            532            
    maxfiles    256            unlimited

To change any of these limits, add a line (you may need to create the file first) to /etc/launchd.conf, the arguments are the same as passed to the launchctl command. For example

echo "limit maxfiles 1024 unlimited" | sudo tee -a /etc/launchd.conf

However launchd has already started your login shell, so the simplest way to make these changes take effect is to restart our machine. (Use >> to append to /etc/launchd.conf.)

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