Master Linux System Backup & Restore: Tar, Rsync, DD & Imaging Guide

Frequent jokes about "deleting the database and running away" highlight the importance of proper backups; without them, a lost system cannot be recovered.

tar command

Backup the whole system on the local machine (ensure enough free space in the root directory).

cd /
# tar.gz format
tar cvpzf system_backup.tar.gz / --exclude=/proc --exclude=/lost+found --exclude=/system_backup.tar.gz --exclude=/mnt --exclude=/sys

# tar.bz2 format
tar cvpjf system_backup.tar.bz2 / --exclude=/proc --exclude=/lost+found --exclude=/system_backup.tar.bz2 --exclude=/mnt --exclude=/sys

# Restore system
cd /
# upload the backup file to the root directory
tar xvpfz system_backup.tar.gz -C /
# or
tar xvpfj system_backup.tar.bz2 -C /

# Directories to exclude when creating backup
mkdir proc
mkdir lost+found
mkdir mnt
mkdir sys

/proc permissions: owner root (r-x), group root (r-x), others (r-x)

/lost+found permissions: owner root (rwx), group root (r-x), others (r-x)

/mnt permissions: owner root (rwx), group root (r-x), others (r-x)

/sys permissions: owner root (rwx), group root (r-x), others (r-x)

After restoration, reboot; the system will be identical to the backup state.

Imaging (backup to a new host)

1. Verify the source system version and install the same version on the target machine with identical partition layout.

lsb_release -a
uname -a
df -Th
free -h

2. Create backup on the source.

# Exclude /dev and /tmp due to hardware differences; add any other exclusions as needed
# Save to /mnt where there is enough space
cd /
tar cvpzf /mnt/system_backup.tar.gz / --exclude=/mnt/system_backup.tar.gz \
    --exclude=/proc --exclude=/lost+found --exclude=/mnt --exclude=/sys \
    --exclude=/dev --exclude=/tmp --exclude=/media
# Upload to target host
scp /mnt/system_backup.tar.gz [email protected]:/mnt

3. On the target, boot from ISO/LiveCD, mount the target disk (usually under /media), and restore.

sudo -s
cd /media/<target-uuid>
# Backup important config files
# Remove existing system directories except the excluded ones
rm -rf root home usr lib lib64 etc var bin sbin opt boot run selinux vmlinuz initrd.img
# Restore backup
mount /dev/vda1 /mnt/1
tar xvpfz system_backup.tar.gz -C /mnt/1
chroot ./
# Edit /etc/fstab and /boot/grub/grub.cfg to match the new UUIDs
# Adjust network and service configurations as needed

After completing these steps, exit the chroot, unmount, and reboot. If GRUB reports errors (e.g., "boot error 15" or "dracut: don't know how to handle root=..."), adjust the GRUB configuration or kernel parameters accordingly.

rsync command

Use rsync for file‑level backups, ensuring the destination partition is formatted with a compatible filesystem (NTFS, FAT, EXT, etc.) to avoid size limitations.

# Backup
rsync -Pa / /media/usb/backup_20170410 --exclude=/media/* --exclude=/sys/* --exclude=/proc/* --exclude=/mnt/* --exclude=/tmp/*
# Restore
rsync -Pa /media/usb/backup_20170410 /

dd command

dd performs sector‑by‑sector cloning; the target partition must be at least as large as the source and the process can be slow.

# Backup
df -h   # check source partition
dd if=/dev/sda1 of=/dev/sdb3   # clone sda1 to sdb3
# Restore
dd if=/dev/sdb3 of=/dev/sda1   # restore sdb3 to sda1