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sysconfigtab - Configurable subsystem definition database file
The sysconfigtab file contains initial values for the attributes of
subsystems that can be dynamically configured. The information in the
sysconfigtab file is loaded into an in-memory kernel database when the
system boots. At subsystem configuration time, values in the in-memory
kernel database override default values coded into the subsystem.
There are multiple numbered versions of the sysconfigtab.* file in the /etc
directory, but only the /etc/sysconfigtab version is used during normal
operations. The versions are present to support the dynamic linking of
modules to create a /vmunix kernel. This feature is called bootlinking and
is documented in Guide to Preparing Product Kits. You may not be able to
use bootlinking if you delete any copies of the sysconfigtab.* file.
Avoid making manual changes to this file. Instead, use the command
sysconfigdb(8) to make changes. This utility will automatically make any
changes available to the kernel and will preserve the structure of the file
so that future upgrades will merge in correctly.
The sysconfigtab file consists of formatted entries. The first line in an
entry specifies the subsystem name. Subsequent lines specify the
subsystems' attributes and values. Comment lines are allowed within an
entry. The following shows the syntax of a subsystem entry:
subsystem-name: #This is a comment describing the subsystem
attribute1 = value1
attribute2 = value2, value3
The following list details sysconfigtab entries:
· The subsystem name is terminated with a colon (:).
· Each attribute name and value pair are terminated with a newline
· Attribute names are separated from values with an equal sign (=).
· No space is allowed in the middle of an attribute name, including an
array attribute name. For instance, array attribute names such as
attr1 and attr1 are permitted, but attr1  or attr1[ 2 ] are
not. For example, the following line in /etc/sysconfigtab is
attr1 = 2
· Attributes that have more than one value separate the values with a
· Quotation marks are not used (") in string values. Blank or tab
characters may occur in the middle of a string, but leading or
trailing blanks are ignored.
· A number sign (#) appears at the beginning of comment lines.
Comments that are specific to the subsystem are placed after the line
containing the subsystem name. The sysconfigdb command considers a
sysconfigtab entry to begin with the subsystem name and end with
either the next subsystem name or the end of the file. Any comments
that appear before a subsystem name are considered to be part of the
preceding subsystem and are deleted if the preceding subsystem is
For a list of the subsystem attributes you can configure, see the System
Administration manual. Refer also to the various sys_attrs reference pages,
which list the system attributes and their default or maximum values. The
graphical user interface dxkerneltuner provides you with an easy way to
review and adjust attribute values.
For information about loadable device driver attributes, see the Writing
Device Drivers: Tutorial manual.
In a cluster environment, an additional clusterwide file,
sysconfigtab.cluster, is used to contain those attributes that must be set
to the same values in each member's /etc/sysconfigtab file. When a cluster
member boots, the contents of its /etc/sysconfigtab file is synchronized
against the clusterwide sysconfigtab.cluster file.
The maximum length of a stanza entry is 40960 bytes. An entry cannot
contain more than 2048 fields (lines).
The maximum length of a stanza field is 500 bytes.
The following shows an example stanza entry that could appear in the
configurable subsystem database:
max-proc-per-user = 64
max-threads-per-user = 256
The preceding entry defines the max-proc-per-user and max-threads-per-user
attributes for the proc subsystem.
Commands: dxkerneltuner(8), sys_attrs(5), sysconfig(8), sysconfigdb(8),
Writing Device Drivers: Tutorial
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