Installation guide

5.3.8 Managing the Subsystem Attributes Database
Information about dynamically configurable subsystem attributes is stored
in the /etc/sysconfigtab database. You use this database to record the
values you want to be assigned to subsystem attributes each time the
system is rebooted or a subsystem is configured. No attributes are set
automatically in this database. If you want to change the default values of
any attributes, you must include the subsystem name, the attribute name,
and the value in the database yourself. You must be the superuser to
modify the /etc/sysconfigtab database.
_______________________ Note _______________________
The /etc/sysconfigtab database might contain stanza
entries from a configurable subsystem’s stanza.loadable file.
This file and the entry in the /etc/sysconfigtab database are
created automatically when you install certain configurable
subsystems. You should not modify these entries in the database.
To add, update, or remove entries in the database, you create a
stanza-format file containing names and values for attributes you want to
modify. (For information about stanza-format files, see stanza
(4)). For
example, suppose you want to set the lockmode attribute in the generic
subsystem to 1. To set this attribute, create a file named, for example,
generic_attrs that has the following contents:
generic:
lockmode = 1
After you create the stanza-format file, you use the /sbin/sysconfigdb
command to update the /etc/sysconfigtab database. You name the
stanza-format file on the command line using the −f flag. The
sysconfigdb command reads the specified file and updates both the
on-disk and in-memory copy of the database. However, the running kernel
is not updated. (Use the sysconfig −r command to update the running
kernel, as described in Section 5.3.6.3.)
The sysconfigdb command has the following syntax:
/sbin/sysconfigdb
[ -a| -d| -l |-m |-r| -s| -u][-f file][subsystem-name]
The sections that follow explain how to use the /sbin/sysconfigdb
command to manage entries in the /etc/sysconfigtab database.
Although it is possible to use a text editor to add, update, or delete
subsystem attributes in the /etc/sysconfigtab database, sysconfigdb
or dxkerneltuner are recommended. For example it is possible to include
Configuring the Kernel 5–13