How to backup centos system

How to backup centos system?

When software or hardware failure causes a system to crash, the system administrator is faced with three tasks to restore it to a fully operational state in the new hardware environment:

1 .Start the rescue system on new hardware.

2. Copy the original storage structure.

3.Restore system and user files.

Regarding the third point, you can use tar to back up and restore files. The first two points can be accomplished using ReaR.

1. Experimental environment

System version: centos 7

Backup software: ReaR (Relax-and -Recover )

Virtual platform: vmware workstation 15.5

2. Configure ReaR

1. Installation related Software package

# yum install rear genisoimage syslinux

2. Configure ReaR

The ReaR configuration file is /etc/rear/local.conf. The main parameters are the following two:

OUTPUT=Output format //First aid system format, such as ISO or USB OUTPUT_URL=Output path //Can be local or SFTP, such as file:/ //mnt/rescue/ represents the local /mnt/rescue/ directory, sftp://backup:password@192.168.0.1/ represents the sftp directory

The system emergency system produced by default is an ISO image file, which is saved in the /var/lib/rear/output/ directory. When the OUTPUT parameter is configured, a copy will be copied to the path set by OUTPUT_URL. Under normal circumstances, we only need one image file, so we can make the following settings to save the file in the /mnt/ directory:

ISO_DIR="/mnt"

3. Backup system

1 .Use tar to back up user and system files, with the -p parameter retaining permissions, the -z parameter using gzip for compression, and --exclude to exclude some directories that do not need to be backed up

# tar -cpzf backup.tar.gz / --exclude=/proc --exclude=/lost+found --exclude=./backup.tgz --exclude=/mnt --exclude=/sys

2. Package the backed up files Save it to other places, such as the host 192.168.0.1

# scp backup.tar.gz root@192.168.0.1:/backup/backup.tar.gz

3. Use ReaR to make an image of the emergency system, and save the image file to other places for recovery use.

# rear -v mkrescue

4. Restore the system

1. Burn the ISO image to a CD and boot from the CD. (Use the ISO image directly in the virtual machine environment)

2. Select the "Recover" recovery option in the menu and enter the command line

3. Run the command to restore the system. (Restore partition and file system)

# rear recover

4. Restore system and user data to the /mnt/local/ directory.

# scp root@192.168.0.1:/backup/backup.tar.gz /mnt/local/    //假设备份的文件在192.168.0.1的主机上，复制到本地# tar xf /mnt/local/backup.tar.gz -C /mnt/local/    //恢复数据# rm -f /mnt/local/backup.tar.gz    //删除备份文件

5. Set the SELinux information to be updated when the system starts.

# touch /mnt/local/.autorelabel

6. Restart the system

# exit    //退出恢复模式，选择yes，安装boot loader# reboot    //重启系统

Related references:centOS tutorial

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