Disk backup, file backup and scheduled backup command guide under Linux

Article directory

Disk backup and scheduled backup command guide
Recommended Python boutique columns
- Basic knowledge of python (0 basic introduction)
- python crawler knowledge

Disk backup and scheduled backup command guide

1 Introduction

In the daily operation and maintenance of computer systems, data backup is a very important task. Whether you are a business or an individual user, you need to back up important data to avoid data loss and damage. As a Linux system administrator, we need to know how to use backup commands to protect data security. This article will introduce the commonly used disk backup command dd and file backup command tar under Linux, as well as the usage and examples of the scheduled backup command crontab.

2. Disk backup command dd

a. Introduction and basic usage

The dd command is a tool that can directly copy data blocks and is suitable for mirror backup of disks. You must be very careful when using this command to avoid corrupting your data.

b. Description of parameters and options of dd command

Commonly used dd command parameters include:

if: is the specified input file or device
of: is the specified output file or device
bs: is the size of the specified data block
count: specifies the number of data blocks to be copied

c. Steps to use dd command to perform disk image backup

Proceed as follows:

Confirm the disk number or device file name to be backed up
Use the dd command to back up disk data
Wait for the backup to complete and check that the size and content of the backup file are correct

d. Methods and precautions for restoring backup data

When using the dd command to restore backup data, the backup data needs to be written back to the target disk. It should be noted that for a formatted disk, partitioning and formatting operations must be performed before the backup data can be successfully restored to it.

e. Example: Use dd command to back up and restore disk image

# 备份磁盘到文件
dd if=/dev/sda of=/backupdir/mirror.img bs=4M

# 恢复备份文件到新磁盘
dd if=/backupdir/mirror.img of=/dev/sdb bs=4M

3. Disk backup command tar

a. Introduction and basic usage

The tar command is a common tool for backing up files. It can package multiple files and directories into one file. It also supports compression and decompression of files and is commonly used to back up user data, configuration files, log records, etc.

b. Description of parameters and options of tar command

Commonly used tar command parameters include:

c: is creating a new backup file
x: is restoring a file from a backup file
v: is to display the detailed backup process
f: is the name of the specified backup file
z: is compressed using gzip

c. Steps to use tar command to backup files and directories

Proceed as follows:

Confirm the files or directories to be backed up
Create a backup file using tar command
Wait for the backup to complete and check that the size and content of the backup file are correct

d. Methods and techniques for compressing and decompressing backup files

To compress and decompress backup files, you can use the compression tools gzip, bzip2 or xz under Linux. A more common method is to combine the compression command with the tar command, as follows:

# 压缩备份文件
tar czvf /backupdir/backup.tar.gz file1.txt directory/

# 解压缩备份文件
tar xzvf /backupdir/backup.tar.gz

e. Example: Use tar command to back up and restore files and directories

# 备份文件和目录
tar cvf /backupdir/backup.tar file1.txt directory

# 恢复备份文件和目录
tar xvf /backupdir/backup.tar -C /restoredir

4. Schedule backup command crontab

a. Introduction and basic concepts

The crontab command can create and manage scheduled tasks on Linux systems to achieve automatic backup. It uses a daemon process called cron that can run user-defined commands or scripts on a specified time period.

b. Syntax and configuration file description of crontab command

Basic syntax of crontab command:

# 编辑用户的定时任务
crontab -e

# 查看用户的定时任务
crontab -l

# 删除用户的定时任务
crontab -r

c. Steps to create and edit crontab scheduled tasks

Proceed as follows:

Edit user's scheduled task list
Add new scheduled tasks, define execution time, commands or scripts
Save and close the scheduled task list

d. Common scheduled backup scenarios and examples

Common scheduled backup scenarios include: daily backup, weekly backup, regular backup, incremental backup, etc. Depending on business needs and data size, different backup methods and strategies can be selected.

e. Example: Use the crontab command to set a scheduled backup task

# 每天凌晨3点备份文件
0 3 * * * tar cvf /backupdir/backup_$(date +\%Y\%m\%d).tar file1.txt directory/

# 每周一凌晨4点备份磁盘
0 4 * * 1 dd if=/dev/sda of=/backupdir/backup_$(date +\%Y\%m\%d).img bs=4M

5. Backup strategies and precautions

When backing up data, different backup types and methods should be used according to the actual situation, such as full backup, incremental backup, differential backup, etc. In order to ensure data security, you also need to pay attention to some details and precautions, such as the storage location of backup data, encryption and integrity verification of backup data, etc.

6 Conclusion

The backup commands dd, tar and the scheduled backup command crontab are all skills that Linux system administrators must master. As an important means of protecting important data, backup can ensure that data will not be lost or damaged due to various accidents. I hope this article will be helpful to you and remind everyone to pay attention to the importance of backing up data. I also hope that everyone will continue to learn and practice backup technology to improve data protection capabilities.

Recommended Python boutique columns

Basic knowledge of python (0 basic introduction)

python crawler knowledge

[python crawler] 1. Basic knowledge of crawlers
[python crawler] 2. Basic knowledge of web pages
[python crawler] 3. First experience with crawlers (BeautifulSoup analysis)
[python crawler] 4. Practical crawler operation (dish crawling)
[python crawler] 5. Practical crawler operation (crawling lyrics)
[python crawler] 6. Practical crawler operation (requesting data with parameters)
[python crawler] 7. Where is the crawled data stored?
[python crawler] 8. Review the past and learn the new
[python crawler] 9. Log in with cookies (cookies)
[python crawler] 10. Command the browser to work automatically (selenium)
[python crawler] 11. Let the crawler report to you on time
[python crawler] 12 .Build your crawler army
[python crawler] 13. What to eat without getting fat (crawler practical exercises)
[python crawler] 14. Scrapy framework explanation
[python crawler] 15. Scrapy framework practice (crawling popular positions)
[python crawler] 16. Summary and review of crawler knowledge points