Red Hat ENTERPRISE LINUX 3 Reference Manual page 86

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For example, this controller is communicating with the CD-ROM at 20 megabytes per second, while
the tape drive is only communicating at 10 megabytes per second.
5.3.9.
/proc/sys/
The directory is different from others in
/proc/sys/
mation about the system but also allows the system administrator to immediately enable and disable
kernel features.
Warning
Use caution when changing settings on a production system using the various files in the
directory. Changing the wrong setting may render the kernel unstable, requiring a system reboot.
For this reason, be sure the options are valid for that file before attempting to change any value in
.
/proc/sys/
A good way to determine if a particular file can be configured, or if it is only designed to provide
information, is to list it with the
configure the kernel. For example, a partial listing of
-r--r--r-- 1 root
-rw-r--r-- 1 root
-r--r--r-- 1 root
-rw-r--r-- 1 root
-r--r--r-- 1 root
In this listing, the files
used to configure the kernel. The other files only provide feedback on current settings.
Changing a value within a
example, to enable the System Request Key on a running kernel, type the command:
echo 1 > /proc/sys/kernel/sysrq
This changes the value for
A few
/proc/sys/
them, place a space character between each value passed with the
this example:
echo 4 2 45 > /proc/sys/kernel/acct
Note
Any configuration changes made using the
To make configuration changes take effect after the system is rebooted, refer to Section 5.4 Using
the Command .
sysctl
The directory contains several subdirectories controlling different aspects of a running
/proc/sys/
kernel.
option at the shell prompt. If the file is writable, it may be used to
-l
root
root
root
root
root
dir-notify-enable
/proc/sys/
from
sysrq 0
configuration files contain more than one value. To correctly send new values to
/proc/
/proc/sys/fs
0 May 10 16:14 dentry-state
0 May 10 16:14 dir-notify-enable
0 May 10 16:14 dquot-nr
0 May 10 16:14 file-max
0 May 10 16:14 file-nr
and can be written to and, therefore, can be
file-max
file is done by echoing the new value into the file. For
(off) to (on).
1
command disappears when the system is restarted.
echo
proc
Chapter 5. The
because it not only provides infor-
looks like the following:
command, such as is done in
echo
File System
/proc/sys/