Learning Devuan GNU/Linux - Backup, Restore & System Maintenance

#Introduction

A backup is the only thing that saves you when a hard disk fails, a file is deleted, or a server gets hit by ransomware. Episode 16 covers backup, restore, and system maintenance on Devuan: backing up files with rsync and dump, using Btrfs snapshots for fast copies, storing package lists with apt-clone, and recovering the system through rescue mode and initramfs.

A good backup strategy combines three things: copied data, a package list that can restore the system, and the ability to boot into repair mode. This episode sets up all three.

#Backing Up Data with rsync

#Local and Remote Synchronization

rsync is the most versatile backup tool. Synchronize a directory to backup media:

sudo apt install rsync
rsync -avz --delete /home/budi/ /mnt/backup/budi/

rsync -avz --delete /home/budi/ /mnt/backup/budi/ copies /home/budi to the backup, preserving attributes (-a), showing progress (-v), and deleting files that no longer exist at the source (--delete). The trailing slash on the source path means the directory's contents are copied into the destination.

#Remote Backup over SSH

For another server or a NAS, combine rsync with SSH:

rsync -avz -e ssh /var/www/ budi@nas:/backup/www/

rsync -avz -e ssh copies data over an encrypted SSH connection. This is the primary backup pattern for production servers — from the source machine to a separate destination machine.

#Test the Restore

A backup without a restore test isn't a backup. Make it a habit to restore part of the data to a temporary location:

rsync -avz /mnt/backup/budi/ /home/budi-restored/
diff -r /home/budi /home/budi-restored

diff -r compares two directories recursively; empty output means the restore succeeded. Schedule restore tests periodically.

#Dump and Snapshots

#Filesystem Backup with dump

For filesystem-level backup with full metadata, use dump:

sudo apt install dump
sudo dump -0uf /mnt/backup/root.dump /

dump -0uf creates a full backup (level 0) of the root filesystem. The resulting file can be restored with restore -rf root.dump. For incremental backups, change the level number as needed.

#Btrfs Snapshots

If your filesystem is Btrfs (episode 10), snapshots are the fastest way to make point-in-time copies:

sudo btrfs subvolume snapshot /mnt/data /mnt/data-snap-$(date +%F)
sudo btrfs subvolume list /mnt

Btrfs snapshots are nearly instant and don't consume the full space — only the changed blocks. To restore one, delete the damaged subvolume and rename the snapshot to data.

#Storing Package Lists with apt-clone

#Cloning the Package State

apt-clone stores the list of installed packages, autoremove state, and dpkg data — perfect for reinstall or migration:

sudo apt install apt-clone
sudo apt-clone clone /mnt/backup/devuan-clone.tar.gz

apt-clone clone produces an archive file containing the system's package state. On a new machine, restore it with:

sudo apt-clone restore /mnt/backup/devuan-clone.tar.gz

Combining rsync for data and apt-clone for packages is an almost painless recipe for reinstalling Devuan.

#Maintenance and Recovery

#Routine Cleanup

Regular maintenance keeps the system healthy:

sudo apt autoremove
sudo apt autoclean
sudo dpkg --configure -a

apt autoremove removes packages no longer needed, apt autoclean cleans up old download archives, and dpkg --configure -a fixes packages that weren't fully configured.

#Recovery via Rescue Mode

If the system can't boot, use the GRUB menu to enter Advanced options and select rescue — or boot from the installation ISO and choose Rescue mode. From there, fix common problems:

mount -t proc proc /target/proc
mount --rbind /dev /target/dev
chroot /target

chroot /target moves your session into the problem system, letting you run update-initramfs -u, fix fstab, or change passwords — all without a full boot.

#Conclusion

Episode 16 covered Devuan backup and maintenance: backing up data with rsync and dump, fast snapshots with Btrfs, storing package state with apt-clone, and recovering the system through rescue mode and chroot for repairs.

Key takeaways:

• rsync is the backbone of backup; always test the restore.
• --delete makes rsync mirror the source exactly.
• dump preserves filesystem metadata; Btrfs snapshots are nearly instant.
• apt-clone stores the package list for fast reinstall.
• Run apt autoremove and autoclean regularly.
• Rescue mode and chroot enable repairs without a full boot.

In the next episode, episode 17, we'll cover Devuan 6.0 Excalibur — the Debian Trixie base with kernel 6.12, eudev by default, GNOME 48 and KDE Plasma 6.3, Python 3.13, OpenSSL 3.5, and Daedalus's role as oldstable.