sysconfigtab(4) — File Formats

NAME

sysconfigtab − Configurable subsystem definition database file

SYNOPSIS

/etc/sysconfigtab

DESCRIPTION

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 character.

•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[1] and attr1[2] are permitted, but attr1 [1] or attr1[ 2 ] are not. For example, the following line in /etc/sysconfigtab is permitted:

attr1[0] = 2

•Attributes that have more than one value separate the values with a comma (,).

•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 deleted.

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.

RESTRICTIONS

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.

EXAMPLES

The following shows an example stanza entry that could appear in the configurable subsystem database:

proc:
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.

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