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<chapter Id="runtime">

<title>Server Setup and Operation</title>

<indexterm><primary>MacOS X</><secondary>IPC configuration</></>

<listitem>

<para>

In OS X 10.2 and earlier, edit the file

<filename>/System/Library/StartupItems/SystemTuning/SystemTuning</>

and change the values in the following commands:

<programlisting>

sysctl -w kern.sysv.shmmax

sysctl -w kern.sysv.shmmin

sysctl -w kern.sysv.shmmni

sysctl -w kern.sysv.shmseg

sysctl -w kern.sysv.shmall

</programlisting>

</para>

<para>

In OS X 10.3 and later, these commands have been moved to

<filename>/etc/rc</> and must be edited there. Note that

<filename>/etc/rc</> is usually overwritten by OS X updates (such as

10.3.6 to 10.3.7) so you should expect to have to redo your edits

after each update.

</para>

<para>

In OS X 10.3.9 and later, instead of editing <filename>/etc/rc</>

you can create a file named <filename>/etc/sysctl.conf</>,

The recommended method for configuring shared memory in OS X

is to create a file named <filename>/etc/sysctl.conf</>,

containing variable assignments such as:

<programlisting>

kern.sysv.shmmax=4194304

kern.sysv.shmseg=8

kern.sysv.shmall=1024

</programlisting>

This method is better than editing <filename>/etc/rc</> because

your changes will be preserved across system updates. Note that

Note that in some OS X versions,

<emphasis>all five</> shared-memory parameters must be set in

<filename>/etc/sysctl.conf</>, else the values will be ignored.

</para>

</para>

<para>

In all OS X versions, you will need to reboot to have changes in the

shared memory parameters take effect.

In older OS X versions, you will need to reboot to have changes in the

shared memory parameters take effect. As of 10.5 it is possible to

change all but <varname>SHMMNI</> on the fly, using

<application>sysctl</>. But it's still best to set up your preferred

values via <filename>/etc/sysctl.conf</>, so that the values will be

kept across reboots.

</para>

<para>

The file <filename>/etc/sysctl.conf</> is only honored in OS X

10.3.9 and later. If you are running a previous 10.3.x release,

you must edit the file <filename>/etc/rc</>

and change the values in the following commands:

<programlisting>

sysctl -w kern.sysv.shmmax

sysctl -w kern.sysv.shmmin

sysctl -w kern.sysv.shmmni

sysctl -w kern.sysv.shmseg

sysctl -w kern.sysv.shmall

</programlisting>

Note that

<filename>/etc/rc</> is usually overwritten by OS X system updates,

so you should expect to have to redo these edits after each update.

</para>

<para>

In OS X 10.2 and earlier, instead edit these commands in the file

<filename>/System/Library/StartupItems/SystemTuning/SystemTuning</>.

</para>

</listitem>

</varlistentry>