Setting Kernel Parameters

[Rick Stevens]

On Thu, 2006-01-12 at 17:34 -0700, E. Craig Brown wrote:
> I am trying to change the default values for kernel parameters
> rmem_default, rmem_max, wmem_default and wmem_max. I modify
> the /etc/sysctl.conf file and add rows:
> rmem_default = 262144
> rmem_max = 262144
> wmem_default = 262144
> wmem_max = 262144
> 
> In case this looks familiar, I am doing this to install an Oracle
> database. I have set the values of other kernel parameters in this
> way, however, when I try to set these and execute sysctl -p, these
> four return a message of 
> error: 'rmem_default' is an unknown key
> error: 'rmem_max' is an unknown key
> error: 'wmem_default' is an unknown key
> error: 'wmem_max' is an unknown key
> Do any of you have any ideas as to why these parameters will not be
> set? I run the command "/sbin/sysctl -a | grep rmem_default" and have
> a message return the current value of each of these as expected. My
> guess is that while I am using the specific string that the Oracle
> Documentation guide suggests to use to change the values of these
> parameters, I probably need a different syntax.

Yes, the keys in the /etc/sysctl.conf file are incorrect.  Modify
your entries to read:

	net.core.rmem_default = 262144
	net.core.rmem_max = 262144
	net.core.wmem_default = 262144
	net.core.wmem_max = 262144

The keys are the full path names under the "/proc/sys" directory, with
the "/"s replaced with dots and the "/proc/sys" bit stripped out.

In your case, the "rmem_default" file is located at

	/proc/sys/net/core/rmem_default

so you drop the "/proc/sys" bit, transliterate the remaining "/"s to 
dots and end up with

	net.core.rmem_default

----------------------------------------------------------------------
- Rick Stevens, Senior Systems Engineer     rstevens at vitalstream.com -
- VitalStream, Inc.                       http://www.vitalstream.com -
-                                                                    -
-              Never eat anything larger than your head              -
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