Proposal: PVE-OS-Rescue Kit - A Bare-Metal USB Backup & Restore utility for the Host OS

[casamia67]

Hi tteck and everyone,
I'd like to propose a new utility for the community: PVE-OS-Rescue Kit.
While we have amazing scripts for LXC and VM backups, many users still struggle with a quick way to backup the entire Host OS to a physical USB stick for disaster recovery.
Key Technical Features:
Live LVM Snapshots: Backs up the root partition without stopping VMs/containers.
Smart Zeroing: Includes a "clean free space" script to shrink a 64GB partition down to a ~6GB compressed image.
Portable Logic: The restore scripts are stored on the USB drive itself, making it a true rescue tool even if the host is partially compromised.
UUID Detection: Automatically tracks the specific USB drive to avoid accidental overwrites.

https://github.com/casamia67/pve-os-rescue

This hybrid approach is a game-changer for Proxmox recovery. By decoupling the OS data from the partition table and bootloader, you’ve solved the "mismatched disk size" headache that usually plagues full-disk clones.
Here is how we should frame this technical distinction for the community:
PVE-OS-Rescue: The Hybrid Advantage
Unlike traditional cloning tools (Clonezilla/dd), this utility focuses on State Restoration:
Hardware Agnostic: Since you start with a clean Proxmox install, the installer handles the local hardware's specific partition alignment, UEFI/BIOS boot, and ZFS/LVM metadata.
The "Debug" Restore: By running the restore script during the Proxmox installer's Debug Mode, you can inject your saved OS state into a freshly prepared environment before the first boot.
Minimalist & Reliable: It avoids the risk of broken GRUB configurations or UUID mismatches on the primary disk, as the foundation is always a native, functional installation.

🚀 PVE-OS-Rescue Kit: Quick Start Guide
This guide explains how to turn a standard USB stick into a disaster recovery tool for your Proxmox host, allowing you to restore your entire OS in minutes—even onto disks of different sizes.
🛠 1. USB Drive Preparation
Plug a USB stick (16GB+ recommended) into your Proxmox server and prepare it to store your backups:
Identify the drive: Use lsblk (e.g., /dev/sdb).
Format to EXT4: Partition and format the drive.
Mount point: mkdir -p /mnt/pve_rescue.
Clone the Repo: Clone the scripts directly onto the USB drive so they are always available.
💾 2. Performing a Live Backup
There is no need to shut down your VMs or containers. The script uses LVM Snapshots to capture a consistent system state while it's running.
Optimization (Smart Zeroing): Run the cleanup script to zero out free space. This shrinks the final backup size significantly (e.g., from 64GB down to ~6GB).
bash
./clean_free_space.sh
Usa il codice con cautela.

Run the Backup:
bash
./backup_os.sh /mnt/pve_rescue
Usa il codice con cautela.

[casamia67]

🛠 Technical Changes (v1.5.1 Update)
Deep-Scan Disk Detection:
Replaced the unreliable findmnt logic with a robust pvs + lsblk combination.
The system now precisely identifies the physical parent disk (e.g., /dev/sda or nvme0n1) directly from the pve Volume Group, preventing "empty directory" backup errors.
Three-Component Synchronized Set:
Moved from a single-file approach to a three-file synchronized set per session:
GPT Layout (.bin): Exact partition structure exported via sgdisk.
Boot Partition (.img): Surgical cloning of the EFI or BIOS Boot partition (automatically detected via fdisk).
OS Root (.img.gz): Compressed LVM snapshot image of the system.
Sequential Bare-Metal Restore:
The restore script now follows a logical recovery sequence:
Rebuild the partition table (Layout).
Inject the Bootloader/GRUB (Boot Part).
Write the system data (OS Image).
This enables restoration onto brand-new, empty disks without needing a pre-installed Proxmox environment.
Smart Snapshot Handling:
Added a pre-check that automatically detects and removes orphaned snapshots (root_snap_backup) before starting, preventing backup locks from previous failed attempts.
Set-Aware Deletion:
The menu deletion option (06) now recognizes the backup timestamp and simultaneously removes all three files in the set, keeping the USB storage clean and consistent.