Managing Systems and Workgroups: A Guide for HP-UX System Administrators

Configuring a System
Reconfiguring the Kernel (HP-UX 11i Version 2)
Chapter 3 371
Console Login: root
Password:
Please wait...checking for disk quotas
...
WARNING: YOU ARE SUPERUSER !!
After the reboot, Susan saves the new kernel configuration under the
name good, so that she can go back to it if needed. She gives it a title to
help recognize it later.
# kconfig -C "Good configuration for Prophet" -s good
* The current configuration has been saved to 'good'.
# kconfig -t good "Good configuration for Prophet"
* The title of the configuration 'good' has been set to "Good
configuration for Prophet".
After some time, one of her users asks her to increase the size of the
buffer cache, hoping to speed up the application. She complies — after
all, it doesn’t need a reboot, so she can do it without disturbing anyone.
Since it’s the first change after a boot, the system asks whether to make
automatic backups.
# kctune -C "Bigger buffer cache for better performance" dbc_max_pct=20
WARNING: The automatic 'backup' configuration currently contains the
configuration that was in use before the last reboot of this
system.
==> Do you wish to update it to contain the current configuration
before making the requested change? yes
* The automatic 'backup' configuration has been updated.
* The requested changes have been applied to the currently
running system.
Tunable Value Expression Changes
dbc_max_pct (before) 10 Default Immed
(now) 20 20
It’s a good thing she said “yes”. The larger buffer cache actually slowed
things down — but all she has to do is restore the automatic backup.
# kconfig -C "Putting buffer cache back; performance was worse." -l backup
* The configuration 'backup' has been loaded.
# kctune dbc_max_pct
Tunable Value Expression Changes
dbc_max_pct 10 Default Immed