Server Maintenance: troubleshooting methods in RHEL5 system

& Nbsp; 1. all files under/boot are lost: (grub, kernel, initrdramdisk) 1. start with bootdisk, enter the liunxrescue mode, and select localinstall or nfs (http) installation method 2. enter the modulo mode: (1 ). cd/mnt/sysimage  

I. All files under/boot are lost: (grub, kernel, initrd ramdisk)

1. start with bootdisk and enter the liunx rescue mode. select local install or nfs (http) installation method.

2. enter the modulo mode:

(1). cd/mnt/sysimage

View some files (if empty)

(2) install kernel:

Cd/mnt/source/Server

Rpm-ivh kernel-2.6.18-53.el5.rpm -- root =/mnt/sysimage -- force

(3) switch/

Chroot/mnt/sysimage

(4) install grub

Grub-install/dev/hda

(5) make initrd ramdisk

Cd/boot

Rm-rf initrd *

Cd/lib/modules

Mkinitrd/boot/initrd-2.6.18-8.el5.img 2.6.18-8

(6) vi/boot/grub. conf

Default = 0

Timeout = 5

Title Entprise Linux 5.0 2.6.18

Root (hd0, 0)

Kernel/vlimuz.2.6.18.el5 ro root = LABEL =/1 rghb quiet

(Note: You can use e2label to view the LABEL)

Initrd/initrd-2.6.18-8.el5.img

(7). exit

(8) reboot

II. Loss of/etc/inittab

Fault description: set to Enter runlevel: it will not change

1. enter rescue mode

2. chroot/mnt/sysimage

3. which package does rpm-qf/etc/inittab belong.

4. exit

5. cd/mnt/source/Server

Rpm-ivh -- replacepkgs -- root/mnt/sysimage init ...... rpm

6. reboot

III. Loss of/etc/fstab

Fault description: starting system logger during mount partition detection

1. enter rescue

2. mkdir/test

3. mount the root partition

(1). use fdisk-l to view the partition, and then use e2label to view the label name of each partition.

(2) mount/dev/hda6/test

(3) cd/test

(4) use e2label to view the label name of each partition

Note: The label names are similar to the directory names for mout.

(5). refer to vi/test/etc/fstab in section 4.

LABEL =/1/ext3 defaults 1 1

LABEL =/boot ext3 defaults 1 1

LABEL =/usr1/usr ext3 defaults 1 1

LABEL =/home ext3 defaults 0 0

/Dev/hda7 swap defaults 0 0

Note: In principle, the three partitions must be mount/,/boot, and swap.

(4) reboot