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Re: semaphores
Przesylam informacje z Progress Knowledgebase (techweb.progress.com),
ktore mam nadzieje pomoga.
Marek Prokop
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KB-19036: SCO Minimum Recommendations for kernel Semaphore Parameters
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SUMMARY:
This document applies to: The Progress RDBMS under the SCO OpenServer
or SCO UNIX System V operating systems.
EXPLANATION:
This information is taken from the SCO Knowledge base #104212, which
states:
The Progress Database makes extensive use of semaphores. The following
tunable kernel parameters should be adjusted to a value at least equal
to the one below:
SEMMNS 300
SEMMNI 100
SEMMSL 50
Note: Configuring the tunable parameters to these values or higher
may result in a warning message. This message can be ignored.
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KB-15411: Modification of SEMMNS and SEMMSL under SCO Unix 5.0.x
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Modification of SEMMNS and SEMMSL under SCO Unix 5.0.x
Written by: Tony Blizniak, Thermoseal, Inc
The Progress Installation manual for version 8(character) discusses
the possibility of requiring the customization of selected kernel
parameters for optimum performance of the database software.
On pages 4-8 and 4-9, the tables show the parameters and their
suggested values. The specific parameters, SEMMNS and SEMMNU
control the number of semaphores provided by the system for use
by the database servers.
The user interface, scoadmin, does not provide access to these
parameters directly, so they must be manually changed using one
of two methods:
Method 1
--------
The command (idtune) will change the value of a parameter as long
as its new value is within the boundaries as defined in the system
file /etc/conf/cf.d/mtune. This file can be viewed with an editor
(vi) for a list of the acceptable minimum and maximum values for
each parameter. Another file that is utilized is
/etc/conf/cf.d/stune. This file is read each time the kernel is
built to apply any user defined changes to the kernel parameters.
It contains all of the parameters that have been modified with new
values.
The idtune command has the following syntax:
/etc/conf/bin/idtune [ -f | -m ] name value
[ -min new_min ] [ -max new_max ]
where name = the name of the parameter, value = the new value
If there is already a value in the stune file, you are prompted to
confirm the change. the (-f) and (-m) options will suppress this
prompt with these conditions:
-f Force the change to stune. Do not output any messages.
-m Do not change the value of the parameter in stune if it
is greater than the new value entered. Do not output any
messages.
Example: to change the value of SEMMNS to 80, enter this command
at the UNIX prompt
#./etc/conf/bin/idtune -f SEMMNS 80
The result of this command is to create an entry in the
/etc/conf/cf.d/stune file for SEMMNS with a value of 80. The
idtune command does not verify that the new value is within the
minimum and maximum range defined in the mtune file. Also, you
should be careful not to invalidate a tunable parameter that
was previously modified earlier or set a value outside the allowable
range unless absolutely necessary. Many add-on packages will
use the idtune command during their setup process to set parameters
at the proper values for their optimum operation. As always, the
kernel must be re-linked after any changes.
Method 2
--------
You can manually edit the stune file to add/change the parameter
value. This method is obviously more dangerous and it should only
be used by an experienced system administrator.
When you re-link the kernel, this new value in the stune file will
be included in the kernel.
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