How to backup and restore system in CentOS

CentOS System Backup and Recovery Guide: Detailed explanation of three common methods

This article will introduce three common methods for system backup and recovery in CentOS system, and provide detailed command examples and precautions to help you choose the most suitable backup plan.

Method 1: Backup and restore using the tar command

The tar command is an efficient archiving tool that can package files and directories into compressed files.

Backup:

 tar cvpzf backup.tgz --exclude=/proc --exclude=/lost found --exclude=/mnt --exclude=/sys /

This command backs up the entire system to a compressed file named backup.tgz and excludes directories such as /proc , /lost found , /mnt and /sys that do not require backup.

recover:

 tar xvpfz backup.tgz -C /

This command extracts the backup.tgz file to the root directory of the system / .

Method 2: Backup and restore using rsync command

rsync is a powerful file synchronization tool that can be used for local or remote backups.

Backup:

 rsync -av --delete /source_directory /destination_directory

Synchronize all contents in the /source_directory directory to the /destination_directory directory. The -a option represents the archive mode, the -v option represents the detailed mode, and the --delete option represents the delete file that does not exist in the source directory in the target directory.

recover:

 rsync -av /source_directory /destination_directory

Synchronize all contents in the /source_directory directory to the /destination_directory directory.

Method 3: Backup and restore using the dd command (use with caution)

The dd command can directly backup the disk and generate disk image files. This method is risky and improper operation may lead to data loss. Please be sure to operate with caution!

Backup:

 dd if=/dev/sda of=backup.img bs=4M

This command backs up the /dev/sda disk to the backup.img file, bs=4M specifies that the block size is 4MB, which speeds up the backup speed. Please replace /dev/sda with your actual disk device name.

recover:

 dd if=backup.img of=/dev/sda bs=4M

This command writes the backup.img file to the /dev/sda disk. Please replace /dev/sda with your actual disk device name.

Important notes:

• Backup space: Make sure there is enough storage space to save backup files.
• Data security: Backup and recovery operations may lead to data loss. Please be sure to operate with caution and backup data in advance.
• Integrity check: Check the integrity and availability of backup files regularly to ensure normal recovery.
• Device name: When using the dd command, be sure to confirm that the disk device name is correct, otherwise it may lead to serious data loss.

Which method to choose depends on your specific needs and technical level. For ordinary users, the tar command may be easier to use; for users who need more granular control and synchronization functions, the rsync command is a better choice; the dd command is suitable for scenarios where a full disk image backup is required, but the risk is also higher. Please choose the appropriate method according to the actual situation.

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