Installation guide

You must reconfigure your kernel, either dynamically or statically, when
one of these situations occurs. The method you use to reconfigure your
kernel depends upon the support provided by the subsystem or subsystem
attributes.
5.2.1 Dynamic Subsystems and Attributes
Some kernel subsystems are dynamically loadable, meaning that you can
add the subsystem to or remove the subsystem from the kernel without
rebuilding the kernel. Often, subsystems that are dynamically loadable also
allow you to dynamically configure the value of their attributes. Therefore,
you can tune the performance of these subsystems without rebuilding the
kernel. If you decide to add or remove these subsystems from the kernel or
configure the value of their attributes, use
dxkerneltuner or the
procedures described in Section 5.3.
Some subsystems, such as required subsystems, are not dynamically
loadable. However, these subsystems might allow you to dynamically
configure the value of attributes. If so, you can configure the value of these
subsystem attributes without rebuilding the kernel.
5.2.1.1 Configuring Subsystems at the Command Line
Tru64 UNIX offers two comman-line methods of dynamically configuring
attributes:
• You can configure the value of attributes in the currently running
kernel using the sysconfig -r command. Only a few kernel
subsystems support this run-time configuration.
• You can configure the value of attributes in the dynamic subsystem
database, /etc/sysconfigtab. When you want to begin running a
kernel that contains the new attribute values, you reboot your system.
The following subsystems provided by Compaq support this type of
boot-time modification:
– dli
− Data link interface subsystem
– generic − Generic kernel subsystem
– ipc − Interprocess communication subsystem
– lsm − Logical Storage Manager
– net − Network subsystem
– presto − Prestoserve subsystem
– proc − Process subsystem
– pts − Pseudoterminal subsystem
Configuring the Kernel 5–3