IBM REDP-4285-00 Manual De Usuario
4285ch04.fm
Draft Document for Review May 4, 2007 11:35 am
102
Linux Performance and Tuning Guidelines
Figure 4-3 /etc/inittab, modified (only part of the file is displayed)
Limiting local terminals
By default, several virtual consoles are spawned locally. The amount of memory used by the
virtual terminals is negligible; nevertheless we try to get the most out of any system.
Additionally, troubleshooting and process analysis will be simplified by simply reducing the
amount of running processes, hence the reason for limiting the local terminals to two.
virtual terminals is negligible; nevertheless we try to get the most out of any system.
Additionally, troubleshooting and process analysis will be simplified by simply reducing the
amount of running processes, hence the reason for limiting the local terminals to two.
To do this, comment out each mingetty ttyx line you want to disable. As an example, in
Figure 4-3 on page 102 we limited the consoles to two. This gives you a fallback local terminal
in case a command kills the shell you were working on locally.
Figure 4-3 on page 102 we limited the consoles to two. This gives you a fallback local terminal
in case a command kills the shell you were working on locally.
4.2.4 SELinux
Red Hat Enterprise Linux 4 introduced a new security model, Security Enhanced Linux
(SELinux), which is a significant step toward higher security. SELinux introduces a mandatory
(SELinux), which is a significant step toward higher security. SELinux introduces a mandatory
... (lines not displayed)
# The default runlevel is defined here
id:3:initdefault:
id:3:initdefault:
# First script to be executed, if not booting in emergency (-b) mode
si::bootwait:/etc/init.d/boot
si::bootwait:/etc/init.d/boot
# /etc/init.d/rc takes care of runlevel handling
#
# runlevel 0 is System halt (Do not use this for initdefault!)
# runlevel 1 is Single user mode
# runlevel 2 is Local multiuser without remote network (e.g. NFS)
# runlevel 3 is Full multiuser with network
# runlevel 4 is Not used
# runlevel 5 is Full multiuser with network and xdm
# runlevel 6 is System reboot (Do not use this for initdefault!)
#
#
# runlevel 0 is System halt (Do not use this for initdefault!)
# runlevel 1 is Single user mode
# runlevel 2 is Local multiuser without remote network (e.g. NFS)
# runlevel 3 is Full multiuser with network
# runlevel 4 is Not used
# runlevel 5 is Full multiuser with network and xdm
# runlevel 6 is System reboot (Do not use this for initdefault!)
#
... (lines not displayed)
# getty-programs for the normal runlevels
# <id>:<runlevels>:<action>:<process>
# The “id” field MUST be the same as the last
# characters of the device (after “tty”).
1:2345:respawn:/sbin/mingetty --noclear tty1
2:2345:respawn:/sbin/mingetty tty2
#3:2345:respawn:/sbin/mingetty tty3
#4:2345:respawn:/sbin/mingetty tty4
#5:2345:respawn:/sbin/mingetty tty5
#6:2345:respawn:/sbin/mingetty tty6
#
#S0:12345:respawn:/sbin/agetty -L 9600 ttyS0 vt102
# <id>:<runlevels>:<action>:<process>
# The “id” field MUST be the same as the last
# characters of the device (after “tty”).
1:2345:respawn:/sbin/mingetty --noclear tty1
2:2345:respawn:/sbin/mingetty tty2
#3:2345:respawn:/sbin/mingetty tty3
#4:2345:respawn:/sbin/mingetty tty4
#5:2345:respawn:/sbin/mingetty tty5
#6:2345:respawn:/sbin/mingetty tty6
#
#S0:12345:respawn:/sbin/agetty -L 9600 ttyS0 vt102
... (lines not displayed)
To start Linux without starting
the GUI, set the run level to 3
the GUI, set the run level to 3
To only provide two local
virtual terminals, comment
out the mingetty entries for
3, 4, 5, and 6.
virtual terminals, comment
out the mingetty entries for
3, 4, 5, and 6.