Tunable Kernel Parameters
Table Of Contents
- Tunable Kernel Parameters
- Legal Notices
- Revision History
- Conventions
- 1 Overview
- 2 Accounting Subsystem
- 3 Asynchronous I/O Subsystem
- 4 File System Subsystem
- 5 Interprocess Communication (IPC) Subsystem
- 6 Kernel Crash Dump Subsystem
- 7 Memory Paging Subsystem
- 8 Process Management Subsystem
- 9 Spinlock Pool
- 10 Streams Subsystem
- 11 Miscellaneous Parameters
- Miscellaneous Parameter Summary
- CD-ROM Parameter Summary
- System Clock Parameter Summary
- Disk I/O Parameter Summary
- Intrusion Detection System/9000
- Fast Symbolic Link Traversal Parameter Summary
- Reserved System Memory Parameter Summary
- Network Parameter Summary
- Queued Signals Parameter Summary
- Real-Time Priority Parameter Summary
- Terminal Parameter Summary
- Maximum Users Parameter Summary
- Web Server Parameter Summary
- Miscellaneous Parameter Summary
- A Table of Tunable Kernel Parameters
Overview
How to Specify Configurable Parameter Values
Chapter 1
13
How to Specify Configurable Parameter Values
All configurable kernel parameters must be specified using an integer value or a formula
consisting of a valid integer expression. All can be specified as an integer, and most can
be specified using a formula; but only a minority are usually specified using formula
values.
Entering Values
Use the kcweb web interface or the kmtune command to view and change values. kcweb
is described in the kcweb (1M) manpage and in the program’s help topics. You can run
kcweb from the command line or from the System Administration Manager (SAM); see
sam (1M). You run kmtune from the command line; see kmtune (1M) for details.
Integer Values
You can use any (optionally signed) integer value.
Formula Values
When using formulas to specify a parameter value, the formula must be an integer
expression. In other words, every element in the expression must be an integer value as
defined for the C programming language.
Configurable parameter names are usually lowercase but the values assigned to them
are specified in formulas as the same name in capitals. For example, the value assigned
to npty (by a C-language #define statement) is NPTY. Thus, a typical formula for nfile
is:
((16*(NPROC+16+MAXUSERS)/10)+32+2*NPTY)
where NPROC represents the defined value of nproc, MAXUSERS represents the defined
value of maxusers, and NPTY represents the defined value for npty. There are a few
isolated exceptions to the uppercase/lowercase rule on certain systems, but they are few.
Whitespace (spaces and tabs) are not allowed.