From f55339577b162d539e357a1cb7e05f3ca54ceaa4 Mon Sep 17 00:00:00 2001
From: Bruce Momjian <bruce@momjian.us>
Date: Sat, 26 Feb 2005 23:19:05 +0000
Subject: [PATCH] Adjust OS-specific kernel settings to mention old and new BSD
methods of adjusting values:
> But to be on the safe side, it would make sense to do something similar
> to the BSD section, and comment about older distributions maybe needing
> to manipulate /proc/kernel/* directly.
Mark Kirkwood
---
doc/src/sgml/runtime.sgml | 46 ++++++++++++++++-----------------------
1 file changed, 19 insertions(+), 27 deletions(-)
diff --git a/doc/src/sgml/runtime.sgml b/doc/src/sgml/runtime.sgml
index 94c03bb5496..3ae948e2586 100644
--- a/doc/src/sgml/runtime.sgml
+++ b/doc/src/sgml/runtime.sgml
@@ -1,5 +1,5 @@
<!--
-$PostgreSQL: pgsql/doc/src/sgml/runtime.sgml,v 1.304 2005/02/10 05:14:58 neilc Exp $
+$PostgreSQL: pgsql/doc/src/sgml/runtime.sgml,v 1.305 2005/02/26 23:19:05 momjian Exp $
-->
<chapter Id="runtime">
@@ -4458,37 +4458,29 @@ option SEMMAP=256
<indexterm><primary>Linux</><secondary>IPC configuration</></>
<listitem>
<para>
- The default shared memory limit (both
- <varname>SHMMAX</varname> and <varname>SHMALL</varname>) is 32
- MB in 2.2 kernels, but it can be changed in the
- <filename>proc</filename> file system (without reboot). For
- example, to allow 128 MB:
+ The default settings are only suitable for small installations
+ (the default max segment size is 32 MB). However the remaining
+ defaults are quite generously sized, and usually do not require
+ changes. The max segment size can be changed via the
+ <command>sysctl</command> interface. For example, to allow 128 MB,
+ and explicitly set the maximum total shared memory size to 2097152
+ pages (the default):
<screen>
-<prompt>$</prompt> <userinput>echo 134217728 >/proc/sys/kernel/shmall</userinput>
-<prompt>$</prompt> <userinput>echo 134217728 >/proc/sys/kernel/shmmax</userinput>
+<prompt>$</prompt> <userinput>systcl -w kernel.shmmax=134217728</userinput>
+<prompt>$</prompt> <userinput>systcl -w kernel.shmall=2097152</userinput>
</screen>
- You could put these commands into a script run at boot-time.
+ In addition these settings can be saved between reboots in
+ <filename>/etc/sysctl.conf.
</para>
<para>
- Alternatively, you can use <command>sysctl</command>, if
- available, to control these parameters. Look for a file
- called <filename>/etc/sysctl.conf</filename> and add lines
- like the following to it:
-<programlisting>
-kernel.shmall = 134217728
-kernel.shmmax = 134217728
-</programlisting>
- This file is usually processed at boot time, but
- <command>sysctl</command> can also be called
- explicitly later.
- </para>
-
- <para>
- Other parameters are sufficiently sized for any application. If
- you want to see for yourself look in
- <filename>/usr/src/linux/include/asm-<replaceable>xxx</>/shmparam.h</>
- and <filename>/usr/src/linux/include/linux/sem.h</>.
+ Older distributions may not have the <command>sysctl</command> program,
+ but equivalent changes can be made by manipulating the
+ <filename>/proc</filename> filesystem:
+<screen>
+<prompt>$</prompt> <userinput>echo 134217728 >/proc/sys/kernel/shmmax</userinput>
+<prompt>$</prompt> <userinput>echo 2097152 >/proc/sys/kernel/shmall</userinput>
+</screen>
</para>
</listitem>
</varlistentry>
--
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