Centos7 system backup and recovery

The following tutorial column of centos will introduce you to Centos7 system backup and recovery. I hope it will be helpful to friends in need!

Centos system backup and recovery tutorial

tar：
Features
1. Retain permissions
2. Suitable for backup The entire directory
3. You can choose different compression methods
4. If you choose not to compress, you can also achieve incremental backup and partial restore. Please refer to man tar

dd
Features
1. Operate on blocks and can back up the entire hard disk (including partition table, MBR, and other file systems that Linux cannot support well)
2. Compression can be performed (a little more troublesome)
3 , since the entire hard disk is backed up, the unused "blank" space on the file system will also be saved, and the backup file is relatively large
Backup
Back up the hard disk sda and put it in /backup (/backup is mounted on other hard disks Such as sdb)

tar method tutorial

Linux is not like Windows, it does not restrict the root user from accessing anything. Therefore, you can completely put each partition on a partition. files into a TAR file.
Use the root user to switch to the root directory
Then, use the following command to back up the complete system:
tar cvpzf backup.tgz / --exclude=/proc --exclude=/lost found --exclude= /backup.tgz --exclude=/mnt --exclude=/sys
or
tar cvpzf /state/partition1/home/backup.tgz / --exclude=/proc --exclude=/lost found - -exclude=/backup.tgz --exclude=/mnt --exclude=/sys
Explanation:
The tar part is the software we will use.
'cvpfz' is the option we added to tar, like "create a compressed archive" (this is obvious), "save permissions" (so that every identical file has the same permissions), and "gzip" (reduce size). Next, is the name the compressed archive will get, in our case backup.tgz.
Following is the root directory we want to back up. Since we want to backup everything :/. Then there are the directories we want to exclude: we don't want to back up everything, because including some directories isn't very useful. Also make sure you don't include the backup file itself, otherwise you'll get weird results. You probably also don't want to include the /mnt folder - if you have other partitions mounted there - otherwise you'll end up backing up those too. Also make sure you don't have anything mounted in /media (i.e. no CDs or removable media mounted). Otherwise, remove /media.
At the end of the process, you might get a message saying "tar: error due to delay from previous error" or something, but in most cases you can just ignore it.
As an option, you can use Bzip to compress your backups. This means higher compression ratio but also lower speed. If the compression ratio is important to you, just replace the "z" in the command with "j" and give the backup name a corresponding extension. These will make the command look like this:
tar cvpjf backup.tar.bz2 / --exclude=/proc --exclude=/lost found --exclude=/backup.tar.bz2 --exclude=/mnt -- exclude=/sys
Recovery:
If the system is destroyed, then we can use the backed up tar package to restore it.
The backup.tgz file in the root directory of the partition
Once again, make sure you are the root user and that the backup file is in the root directory of the file system.

One of the beauties of Linux is that this can even be done on a running system; there's no need to get confused by a boot CD or anything. Of course, if you make your system unbootable. You may have no choice but to use a live-CD, but the result is the same. You can even remove all the files in your Linux system while it is running. But I won’t tell you that order!
This is the command I would use:
tar xvpfz backup.tgz -C /
If you are using bz2:
tar xvpfj backup.tar.bz2 -C /
Warning: This will Replace all files in your partition with files in the compressed archive!
Make sure before you do anything else, re-create the directory you culled:
mkdir proc
mkdir lost found
mkdir mnt
mkdir sys
/proc Permissions: File Owner :root group: root owner: read execution group: read execution other: read execution
/lost found permissions: file owner: root group: root owner: read write execution group : Read and execute Others: Read and execute
/mnt Permissions: File owner: root Group: root Owner: Read and write Execute group: Read and execute Others: Read and execute
/sys Permissions :File Owner: root Group: root Owner: Read Write Execution Group: Read Execution Others: Read Execution
When you restart, everything will be exactly the same as when you backed up.

Users refer to the above tutorial for backup and recovery, and generally report that after restarting the computer, they will still be prompted to enter the user name and password. .

Someone mentioned on the Internet: I consulted experts and found a solution. After restoring, execute the following command and then restart to solve this problem: restorecon -Rv /

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