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Essential Proxmox Configuration Backup Strategy

ProxmoxBackupDisaster RecoveryHomelabZFSSystem Administration

Essential Proxmox Configuration Backup Strategy

This guide shows you how to create a comprehensive backup of your Proxmox VE configuration to a USB drive. When your homelab has GPU passthrough, custom networking, and multiple VMs, having a solid backup of your configuration is critical for disaster recovery.

What You'll Backup

A complete Proxmox configuration backup including:

  • All VM and container configurations
  • GRUB bootloader settings
  • Kernel and initramfs images
  • VFIO and module configurations
  • Proxmox VE settings
  • ZFS pool information

System Specifications

Requirements

  • USB Drive: 8GB+ recommended
  • Filesystem: ext4 or FAT32
  • Proxmox Access: Root or sudo privileges
  • Time Required: 5-10 minutes

What Gets Backed Up

  • VM configs: /etc/pve/qemu-server/
  • Boot configs: /etc/default/grub, /boot/
  • Module configs: /etc/modprobe.d/, /etc/modules
  • PVE configs: /etc/pve/
  • ZFS metadata: Pool lists and properties

Prerequisites

Before starting:

  1. USB drive formatted and ready
  2. Root access to Proxmox host
  3. USB drive device identified (e.g., /dev/sdc)

Part 1: Prepare USB Drive

Step 1: Identify USB Drive

Insert USB drive and identify it:

lsblk

Look for your USB drive (e.g., sdc).

Warning: Ensure you identify the correct device! Wrong device could cause data loss.

Step 2: Create Mount Point and Mount

mkdir -p /mnt/usb
mount /dev/sdc1 /mnt/usb

Note: Adjust partition number (sdc1, sdc2, etc.) based on your drive layout.

Verify mount:

df -h | grep usb

Part 2: Backup VM Configurations

Step 3: Backup All VM Configs

mkdir -p /mnt/usb/backup/qemu-server
cp -r /etc/pve/qemu-server/* /mnt/usb/backup/qemu-server/

What this backs up:

  • All VM configurations (.conf files)
  • CPU, memory, disk assignments
  • Network configurations
  • PCI passthrough settings
  • Boot order and options

Example backup: VM 100's configuration at /mnt/usb/backup/qemu-server/100.conf

Part 3: Backup Boot Configuration

Step 4: Backup GRUB Configuration

mkdir -p /mnt/usb/backup/grub
cp /etc/default/grub /mnt/usb/backup/grub/default-grub
cp -r /boot/grub /mnt/usb/backup/grub/boot-grub-folder

Why this matters:

  • GRUB contains IOMMU settings
  • Custom kernel parameters
  • Boot order and timeout settings

Step 5: Backup Kernel and Initramfs

mkdir -p /mnt/usb/backup/boot
cp /boot/initrd.img-$(uname -r) /mnt/usb/backup/boot/
cp /boot/vmlinuz-$(uname -r) /mnt/usb/backup/boot/
tar czvf /mnt/usb/backup/boot/boot-full-backup.tar.gz /boot

What this backs up:

  • Current kernel image
  • Initramfs with all modules
  • Complete /boot directory archive

Recovery use: If boot fails, you can restore exact kernel that was working.

Part 4: Backup Module Configurations

Step 6: Backup VFIO and Module Configs

mkdir -p /mnt/usb/backup/modprobe
cp /etc/modprobe.d/* /mnt/usb/backup/modprobe/

mkdir -p /mnt/usb/backup/modules-load
cp /etc/modules-load.d/* /mnt/usb/backup/modules-load/

cp /etc/modules /mnt/usb/backup/modules

Critical files backed up:

  • vfio.conf: GPU passthrough bindings
  • blacklist.conf: Disabled modules (nouveau, nvidia)
  • /etc/modules: Modules loaded at boot

Why critical: GPU passthrough requires specific module loading order and blacklists.

Part 5: Backup Proxmox Configuration

Step 7: Backup PVE Configuration Files

mkdir -p /mnt/usb/backup/pve
cp -r /etc/pve/* /mnt/usb/backup/pve/

What this includes:

  • Cluster configuration
  • User permissions and roles
  • Storage configurations
  • Network settings (SDN)
  • Firewall rules
  • Ceph configuration (if used)

Note: This backs up the entire Proxmox VE configuration database.

Part 6: Backup ZFS Metadata

Step 8: Export ZFS Configuration

zfs list > /mnt/usb/backup/zfs-dataset-list.txt
zfs get all > /mnt/usb/backup/zfs-dataset-properties.txt

What this captures:

  • All ZFS datasets and volumes
  • Compression settings
  • Quota configurations
  • Snapshot policies
  • Mount points

Recovery use: Recreate ZFS structure with same properties if pool needs rebuilding.

Part 7: Finalize Backup

Step 9: Create Backup Manifest

Document what was backed up:

cat > /mnt/usb/backup/BACKUP_INFO.txt << EOF
Proxmox Backup
Date: $(date)
Hostname: $(hostname)
Proxmox Version: $(pveversion)
Kernel: $(uname -r)

Backed up:
- VM configs from /etc/pve/qemu-server/
- GRUB config from /etc/default/grub
- Kernel and initramfs from /boot/
- Module configs from /etc/modprobe.d/
- PVE configs from /etc/pve/
- ZFS metadata

To restore:
1. Mount this USB drive
2. Copy files back to original locations
3. Update initramfs: update-initramfs -u -k all
4. Update GRUB: update-grub
5. Reboot
EOF

Step 10: Verify Backup

Check backup contents:

ls -lah /mnt/usb/backup/
tree /mnt/usb/backup/ | head -20

Verify file sizes are reasonable:

du -sh /mnt/usb/backup/*

Step 11: Unmount USB Drive

Safely unmount:

umount /mnt/usb

Remove USB drive and label it: Proxmox Backup - [DATE]

Part 8: Restoration Process

How to Restore from Backup

After a fresh Proxmox install:

  1. Mount backup USB:
mkdir -p /mnt/usb
mount /dev/sdc1 /mnt/usb
  1. Restore GRUB config:
cp /mnt/usb/backup/grub/default-grub /etc/default/grub
update-grub
  1. Restore module configs:
cp /mnt/usb/backup/modprobe/* /etc/modprobe.d/
cp /mnt/usb/backup/modules /etc/modules
  1. Restore VM configs:
cp /mnt/usb/backup/qemu-server/* /etc/pve/qemu-server/
  1. Update initramfs:
update-initramfs -u -k all
  1. Reboot:
reboot

Automation Script

Create Automated Backup Script

Create script:

nano /usr/local/bin/proxmox-backup.sh

Add this content:

#!/bin/bash

# Configuration
USB_MOUNT="/mnt/usb"
BACKUP_DIR="${USB_MOUNT}/backup"
DATE=$(date +%Y%m%d)

# Check if USB is mounted
if ! mountpoint -q ${USB_MOUNT}; then
    echo "Error: USB drive not mounted at ${USB_MOUNT}"
    exit 1
fi

echo "Starting Proxmox backup..."

# Create timestamped backup directory
mkdir -p ${BACKUP_DIR}-${DATE}
cd ${BACKUP_DIR}-${DATE}

# VM Configs
echo "Backing up VM configs..."
mkdir -p qemu-server
cp -r /etc/pve/qemu-server/* qemu-server/

# GRUB
echo "Backing up GRUB..."
mkdir -p grub
cp /etc/default/grub grub/

# Modules
echo "Backing up module configs..."
mkdir -p modprobe modules-load
cp /etc/modprobe.d/* modprobe/ 2>/dev/null
cp /etc/modules-load.d/* modules-load/ 2>/dev/null
cp /etc/modules modules

# PVE configs
echo "Backing up PVE configs..."
mkdir -p pve
cp -r /etc/pve/* pve/

# ZFS
echo "Backing up ZFS metadata..."
zfs list > zfs-dataset-list.txt
zfs get all > zfs-dataset-properties.txt

# Create info file
cat > BACKUP_INFO.txt << EOF
Proxmox Backup
Date: $(date)
Hostname: $(hostname)
Proxmox Version: $(pveversion)
Kernel: $(uname -r)
EOF

echo "Backup complete: ${BACKUP_DIR}-${DATE}"
echo "Size: $(du -sh ${BACKUP_DIR}-${DATE} | cut -f1)"

Make executable:

chmod +x /usr/local/bin/proxmox-backup.sh

Run Automated Backup

mount /dev/sdc1 /mnt/usb
/usr/local/bin/proxmox-backup.sh
umount /mnt/usb

Best Practices

Backup Schedule

Recommended frequency:

  • After major configuration changes (immediately)
  • Before Proxmox updates (always)
  • Monthly for stable systems
  • Weekly for development/testing systems

Storage Recommendations

  1. Multiple USB drives: Rotate between 2-3 drives
  2. Offsite backup: Keep one backup offsite
  3. Test restores: Periodically verify backups are restorable
  4. Document changes: Note what changed since last backup

What This Doesn't Backup

Not included (requires separate strategy):

  • VM disk images (use Proxmox Backup Server or vzdump)
  • Container data
  • ZFS pool data (only metadata)
  • Large media files

Troubleshooting

Issue: Can't mount USB drive

Solutions:

  1. Check filesystem:
lsblk -f
  1. If no filesystem, create one:
mkfs.ext4 /dev/sdc1
  1. Check USB errors:
dmesg | tail -20

Issue: Permission denied copying files

Solutions:

  1. Run as root:
sudo -i
  1. Check USB mount permissions:
mount | grep usb

Issue: Backup too large for USB

Solutions:

  1. Exclude boot archive (largest file):
# Skip the tar.gz line in backup script

  1. Use larger USB drive (16GB+)

  2. Compress individual directories:

tar czvf pve-backup.tar.gz /etc/pve/

Recovery Scenarios

Scenario 1: Lost GPU Passthrough Config

Restore module configs and GRUB:

cp /mnt/usb/backup/modprobe/* /etc/modprobe.d/
cp /mnt/usb/backup/grub/default-grub /etc/default/grub
update-grub
update-initramfs -u -k all
reboot

Scenario 2: Corrupted VM Config

Restore single VM:

cp /mnt/usb/backup/qemu-server/100.conf /etc/pve/qemu-server/

Scenario 3: Fresh Proxmox Install

Follow full restoration process in Part 8.

Conclusion

You now have a comprehensive backup strategy for your Proxmox configuration:

  • ✓ All critical configs backed up to USB
  • ✓ Fast disaster recovery capability
  • ✓ Protection against configuration loss
  • ✓ Documented restoration process
  • ✓ Automated backup script

Regular backups ensure you can quickly recover from hardware failures, misconfigurations, or system corruption.

Next steps:

  • Set up automated VM backups with Proxmox Backup Server
  • Configure ZFS snapshots for data protection
  • Implement 3-2-1 backup strategy (3 copies, 2 media types, 1 offsite)
  • Document your complete infrastructure