How to back up and restore a CentOS system

Use rsync for full system backups by mounting a target drive and running rsync with archive, ACL, and extended attribute preservation while excluding virtual filesystems, then unmount after completion. 2. Create compressed system backups with tar by excluding temporary directories and compressing the root filesystem into a .tar.gz file, and restore by extracting it in a chroot environment after reinstalling GRUB. 3. Perform selective backups of critical directories like /home, /etc, /var/www, and /var/lib/mysql using tar, automate with a script, and schedule via cron for routine protection. 4. Restore full backups by booting from live media, partitioning the target disk, mounting the root partition, restoring files, reinstalling the bootloader, and updating /etc/fstab if needed, or restore selective data by extracting specific archives and restarting services. 5. Ensure reliability by regularly testing restores, storing backups offsite, verifying disk layouts with lsblk and blkid, maintaining a package list for quick reinstallation, and considering LVM snapshots for consistent live backups, with rsync or tar being optimal for most CentOS users due to simplicity and control.

Backing up and restoring a CentOS system is essential for disaster recovery, hardware migration, or system upgrades. A solid backup strategy ensures you can recover your data, configurations, and operating system quickly. Below are practical methods to back up and restore a CentOS system effectively.

1. Full System Backup Using rsync

rsync is a reliable and widely used tool for creating complete system backups. It copies files incrementally and preserves permissions, ownership, and symlinks.

Steps to Back Up with rsunk:

1. Boot into a live environment (optional but recommended for consistency).

   

2. Mount your target backup drive (e.g., external disk or network location):

   mkdir /mnt/backup
   mount /dev/sdb1 /mnt/backup

3. Run rsync to copy the entire system (exclude temporary and virtual filesystems):

   

   rsync -aAXv --exclude={"/dev/*","/proc/*","/sys/*","/tmp/*","/run/*","/mnt/*","/media/*","/lost found"} / /mnt/backup/

   • -a: Archive mode (preserves permissions, symlinks, etc.)
   • -A: Preserve ACLs
   • -X: Preserve extended attributes
   • -v: Verbose output

4. After backup completes, unmount:

   umount /mnt/backup

This method works well for full system images and supports incremental backups.

2. Using tar for System Backup

tar is another powerful tool for creating compressed system backups.

Create a Full Backup:

tar --exclude=/proc --exclude=/sys --exclude=/dev --exclude=/run --exclude=/mnt --exclude=/media --exclude=/tmp -czf /backup/centos-backup.tar.gz /

• -c: Create archive
• -z: Compress with gzip
• -f: Specify filename

Store the .tar.gz file on an external drive or remote server.

Restore from tar Backup:

1. Boot from a CentOS live USB/CD.

2. Mount your root partition:

   mount /dev/sda1 /mnt

3. Extract the backup:

   tar -xzf /backup/centos-backup.tar.gz -C /mnt/

4. Reinstall GRUB (if needed):

   mount --bind /dev /mnt/dev
   mount --bind /proc /mnt/proc
   mount --bind /sys /mnt/sys
   chroot /mnt
   grub2-install /dev/sda
   grub2-mkconfig -o /boot/grub2/grub.cfg
   exit

5. Reboot.

3. Backup Important Data and Configurations (Selective)

For routine backups, focus on critical directories:

• /home – user data
• /etc – system configuration
• /var/www – web content
• /var/lib/mysql – databases
• /opt – third-party software

Example backup script:

#!/bin/bash
BACKUP_DIR="/backup/$(date  %F)"
mkdir -p $BACKUP_DIR

tar -czf $BACKUP_DIR/home.tar.gz /home
tar -czf $BACKUP_DIR/etc.tar.gz /etc
tar -czf $BACKUP_DIR/mysql.tar.gz /var/lib/mysql

# Optional: Copy to remote server
scp $BACKUP_DIR/*.tar.gz user@remote:/backup/

Schedule it via cron:

0 2 * * * /usr/local/bin/backup.sh

4. Restore Process Overview

Restoration depends on your backup method:

• rsync or tar full system backup:

  • Boot from live media.
  • Partition and format the target disk.
  • Mount the root partition and restore files.
  • Reinstall bootloader (GRUB).
  • Update /etc/fstab if UUIDs changed.

• Selective data restore:

  • Extract needed .tar.gz files to appropriate locations.
  • Restart services (e.g., systemctl restart httpd mysqld).

5. Tips for Reliable Backups

• Test your restore process regularly.

• Store backups offsite or on separate hardware.

• Use lsblk and blkid to verify disk layouts before restoring.

• Keep a list of installed packages:

  rpm -qa > package-list.txt

  Restore with:

  yum install $(cat package-list.txt)

• Consider using LVM snapshots for consistent backups on running systems.

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Final Notes

There are also advanced tools like Bacula, Amanda, or Clonezilla for enterprise or disk-image-based backups. But for most CentOS users, rsync or tar offers simplicity, control, and reliability.

Choose the method that fits your environment—full system image for disaster recovery, selective backups for daily use.

Basically, back up early, back up often, and always verify you can restore.

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