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Andrew Lauer Barinov
Asked: 2012-04-28 17:08:48 +0800 CST

Modifying kernel shared memory settings on a lion install

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What's the location of the sysctl.conf file on lion? In Snow Leopard it was in /etc/sysctl.conf but now that folder doesn't contain it anymore. Searching for the file in spotlight yields no results.

Have the shared memory settings been moved to a different conf file? What is it's name?

EDIT

I am trying to modify the kernel shared memory settings of the machine. When I didn't find the sysctl.conf file in the right place, I created my own with the recommended settings and put into /etc directory. However running sysctl -a still shows me that the old memory settings are in place.

How do I go about modifying these settings on a lion install?

mac-osx sysctl osx-lion

2 Answers

  1. The location is still /etc/sysctl.conf or more precisely /private/etc/sysctl.conf. I had to tweak some settings because I wanted to run Postgresql on my machine and it turned out that I had to modify all of the five settings in order to get it running. So I created the file and put in something like this:

    kern.sysv.shmmax=1610612736
kern.sysv.shmmin=1
kern.sysv.shmmni=256
kern.sysv.shmseg=64
kern.sysv.shmall=393216

    Then I rebooted and it's been working ever since...

    NB you don't have to reboot, you can use:

    sudo sysctl -w kern.sysv.shmmax=1610612736

    etc....

    This makes the changes in real time, the file will make them persist between reboots

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  2. Best Answer

    I believe /etc/sysctl.conf is still the right place (and man sysctl.conf agrees).

    Did you reboot? changes to /etc/sysctl.conf are not a real-time thing: They are only read/applied when the system enters multi-user mode during startup.

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