CentOS three methods for restoring Disk Data

CentOS three methods for restoring Disk Data

This article uses the OEL5.8x64 system, the file system uses LVM volumes, there is also a general disk partition mounting for testing.

Data Recovery is required as follows:
(1) The operating system is damaged due to power failure or other causes, and the system cannot be properly guided or the network service cannot be started.
(2) disk-related hardware faults, such as RAID 1 and RAID 5, which can be forcibly started but will soon fail, A critical State occurs when the disk array is restarted before disk replacement. In this case, the data can be recovered.
(3) This document does not describe how to recover data in case of accidental deletion in a linux system, nor how to recover the system, but how to retrieve disk data in case of system failure.
This article from: http://koumm.blog.51cto.com

Method 1: single-user mode

Note: The single-user mode is similar to the rescue mode. The rescue mode is advantageous only when the boot disk is used for boot. files such as fstab, passwd, and inittab are damaged and cannot be mounted on an LVM disk, other methods are required.

1.Description of Single User Mode

The single-user mode is the linux emergency start mode. You must use the console to start a connection. In this case, the system does not have a network or related services, and no password is required for logon, it is a way to determine the severity of operating system faults. You can change the password in single-user mode.

(1) Press edit E mode under the GRUB menu.

(2) Select the KERNEL row

(3) Enter 1 or single and press Enter.

(4) Start By B

(5) enter the prompt

3.Start NETWORK SERVICE

4.Start the SSH service

Then, you can use ssh and other network command tools to copy disk data.

Scp-r

The client ssh client tool copies data.

Rsync

Method 2: boot disk CFT-0.5.9

(CFT-0.5.9 is for IBM server WINPE boot disk, the current WINPE boot disk for PC, for the server because there is no array card driver can not identify the disk. CFT-0.5.9WINPE for IBM server to add disk array, also has WINPE commonly used command tools, in a IBMx3650M3 server windows2003 system due to the wrong configuration caused by the wrong password, the disk successfully solved the problem, it is strongly recommended.

1.Enable the ext2volumemanager tool after startup

This tool can only open common Linux partitions, such as ext2, ext3, and ext4. LVM partitions cannot be opened. This RAW format is LVM partition.

Partition 19Gext3.

The disk partition is successfully opened and data on the disk can be directly copied.

Method 3: LiveCD/LiveDVD boot disk

CentOS-6.5-LiveDVD boot Disc:
Http://mirrors.163.com/centos/6.5/isos/x86_64/CentOS-6.5-x86_64-LiveDVD.iso

1. Use a CentOS-6.5-LiveDVD boot disc to open the terminal window.

2. Check the identified disk and identify whether it is an LVM volume or a common disk partition.

3. You can directly Mount common disk partitions.

4. For mounting logical volume disks, The livecd/livedvd command can be used to process LVM disks.

(1) Scanning physical volumes and volume groups

(2) activate the physical volume and volume group

# Vgchange-ayVolGroup00

(3) mount a logical volume

It can be mounted normally.

(4) You can copy data by using a USB flash drive or an SSH tool.

The above method can provide more methods for linux disk data to be taken out abnormally.

This article is from the "koumm linux technology blog" blog, please be sure to keep this source http://koumm.blog.51cto.com/703525/1377027