系统启动-——故障排查

Posted 2021-02-03

实验目标：

分别删除/boot下的initramfs-2.6.32-358.el6.x86_64.img和vmlinuz-2.6.32-358.el6.x86_64文件
然后挂载光盘，进入救援模式进行故障恢复。

实验前先查看/boot 下initramfs-2.6.32-358.el6.x86_64.img 文件属性和内容：

方法一：
===================================================================================================================
[[email protected] boot]#cp initramfs-2.6.32-358.el6.x86_64.img /data/    //为了查看，先把此文件拷贝到/data目录下

[[email protected] data]#file initramfs-2.6.32-358.el6.x86_64.img         //查看文件类型
initramfs-2.6.32-358.el6.x86_64.img: gzip compressed data, from Unix, last modified: Fri Mar  7 06:01:26 2014, max compression 

[[email protected] data]#gunzip initramfs-2.6.32-358.el6.x86_64.img       //直接解压报错
gzip: initramfs-2.6.32-358.el6.x86_64.img: unknown suffix -- ignored

[[email protected] data]#mv initramfs-2.6.32-358.el6.x86_64.img initramfs-2.6.32-358.el6.x86_64.img.gz  //文件改名为.gz后缀
[[email protected] data]#ls
initramfs-2.6.32-358.el6.x86_64.img.gz   

[[email protected] data]#gzip -d initramfs-2.6.32-358.el6.x86_64.img.gz   //然后解压

[[email protected] data]#ll /boot/initramfs-2.6.32-358.el6.x86_64.img initramfs-2.6.32-358.el6.x86_64.img   //对比原文件和解压后的文件
-rw-r--r--. 1 root root 16583044 Mar  7  2014 /boot/initramfs-2.6.32-358.el6.x86_64.img   //原文件
-rw-r--r--  1 root root 46944256 Jan 15 09:39 initramfs-2.6.32-358.el6.x86_64.img          //解压后

[[email protected] data]#file initramfs-2.6.32-358.el6.x86_64.img   //再次查看文件类型为cpio格式文件
initramfs-2.6.32-358.el6.x86_64.img: ASCII cpio archive (SVR4 with no CRC)

[[email protected] data]#cpio -id <initramfs-2.6.32-358.el6.x86_64.img   //文件解压成功
91688 blocks
[[email protected] data]#ls   //查看发现这是一个最小化的Linux运行环境
bin                 emergency  initqueue-finished                   lib        pre-trigger  sys      var
cmdline             etc        initqueue-settled                    lib64      pre-udev     sysroot
dev                 init       initqueue-timeout                    mount      proc         tmp
dracut-004-303.el6  initqueue  initramfs-2.6.32-358.el6.x86_64.img  pre-pivot  sbin         usr

方法二：
==============================================================================================================
[[email protected] test]#zcat initramfs-2.6.32-754.el6.x86_64.img |cpio -id //查看后，管道给cpio解压
141150 blocks
[[email protected] test]#ls
bin emergency initqueue-finished lib pre-mount proc tmp
cmdline etc initqueue-settled lib64 pre-pivot sbin usr
dev init initqueue-timeout mount pre-trigger sys var
dracut-004-411.el6 initqueue initramfs-2.6.32-754.el6.x86_64.img netroot pre-udev sysroot

===============================================================================================================

故障救援

1、删除initramfs-2.6.32-358.el6.x86_64.img，然后再恢复

[[email protected] boot]#rm -rf initramfs-2.6.32-358.el6.x86_64.img  //删除文件

[[email protected] boot]#reboot  //重启，发现系统起不来

F:ISO系统文件
hel-server-6.4-x86_64-dvd.iso   //救援之前第一步先挂载挂载光盘

连接光盘-->重置---> 鼠标点进虚拟机 --> 按一下ESC键

sh-4.1# chroot /mnt/sysimage/    //切根
sh-4.1# mkinitrd /boot/initramfs-`uname -r`.img `uname -r`  //为当前正在使用的内核重新制作ramdisk文件
sh-4.1# ll /boot
total 22866
-rw-r--r--. 1 root root   104081 Jan 30  2013 config-2.6.32-358.el6.x86_64
drwxr-xr-x. 3 root root     1024 Mar  7  2014 efi
drwxr-xr-x. 2 root root     1024 Mar  7  2014 grub
-rw-r--r--. 1 root root 16647561 Jan 15 11:11 initramfs-2.6.32-358.el6.x86_64.img  //删除的文件已经恢复
drwx------. 2 root root    12288 Mar  7  2014 lost+found
-rw-r--r--. 1 root root   185734 Jan 30  2013 symvers-2.6.32-358.el6.x86_64.gz
-rw-r--r--. 1 root root  2407466 Jan 30  2013 System.map-2.6.32-358.el6.x86_64
-rwxr-xr-x. 1 root root  4044560 Jan 30  2013 vmlinuz-2.6.32-358.el6.x86_64

重启电脑，成功进入系统。

2、 删除vmlinuz-2.6.32-358.el6.x86_64， 然后再恢复

[[email protected] boot]#reboot //重启后报错

 Error 15: File not found

 Press any key to continue. . . 

F:ISO系统文件
hel-server-6.4-x86_64-dvd.iso   //救援之前第一步先挂载挂载光盘

连接光盘-->重置---> 鼠标点进虚拟机 --> 按一下ESC键

sh-4.1# chroot /mnt/sysimage/    //切根
sh-4.1# mount /dev/cdrom  /mnt   //挂光盘
sh-4.1# cd /mnt/isolinux/
sh-4.1# cp vmlinuz /boot/vmlinuz-`uname -r`   //恢复删除的Linux内核文件到/boot/

重启电脑，成功进入系统。