在启动过程中更改默认控制台日志级别 [英] Change default console loglevel during boot up

问题描述

我设置了一个CentOS 6.3安装程序，在该程序上，控制台日志级别设置为4，默认日志级别设置为4.我知道我可以使用以下步骤来更改默认控制台日志级别:

I setup a CentOS 6.3 setup, on which the console loglevel is set to 4, and default log level is set to 4. I know I can change the default console log level using the following steps:

cat /proc/sys/kernel/printk

4   4   1   7

echo 5 > /proc/sys/kernel/printk
cat /proc/sys/kernel/printk

5   4   1   7

但是，重新启动后，控制台日志级别将恢复为原始值.我是否需要重新编译内核，或者有什么方法可以使更改后的值在重新启动后保持不变.

However, upon reboot, the console log level reverts back to the original value. Do I need to recompile the kernel, or is there a way I can get the changed value to be persistent across reboot.

推荐答案

我是否需要重新编译内核，

Do I need to recompile the kernel,

否.

还是有一种方法可以使更改后的值在重新启动后保持不变.

or is there a way I can get the changed value to be persistent across reboot.

是的
使用内核命令行参数loglevel:

Yes.
Use the kernel command line parameter loglevel:

loglevel=       All Kernel Messages with a loglevel smaller than the
                    console loglevel will be printed to the console. It can
                    also be changed with klogd or other programs. The
                    loglevels are defined as follows:

                    0 (KERN_EMERG)          system is unusable
                    1 (KERN_ALERT)          action must be taken immediately
                    2 (KERN_CRIT)           critical conditions
                    3 (KERN_ERR)            error conditions
                    4 (KERN_WARNING)        warning conditions
                    5 (KERN_NOTICE)         normal but significant condition
                    6 (KERN_INFO)           informational
                    7 (KERN_DEBUG)          debug-level messages

内核命令行上所有可能的参数列表位于

The entire list of parameters possible on the kernel command line are in the Linux/Documentation/kernel-parameters.txt file in the source tree.

根据您的引导程序(例如Grub或U-Boot)，您将必须编辑文本以将此新参数添加到命令行中.使用cat /proc/cmdline查看用于上一次引导的内核命令行.

Depending on your bootloader (e.g. Grub or U-Boot), you will have to edit text to add this new parameter to the command line. Use cat /proc/cmdline to view the kernel command line used for the previous boot.

附录

要显示所有内容，为loglevel参数提供的数字应大于KERN_DEBUG.
也就是说，您必须指定loglevel=8.
或者直接使用ignore_loglevel参数显示所有内核消息.

To display everything, the number supplied for the loglevel parameter would have be be greater than KERN_DEBUG.
That is, you would have to specify loglevel=8.
Or simply use the ignore_loglevel parameter to display all kernel messages.

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