How to use the command 'qmrestore' (with examples)

The qmrestore command is a utility used primarily within the Proxmox Virtual Environment to restore QemuServer virtual machines from VZDump backup files. Proxmox is a robust open-source server management platform heavily utilized for virtualization, and qmrestore serves as a vital tool within this platform’s suite of commands. This command allows administrators to recovery virtual machines from backups, ensuring data preservation and continuity in case of system failures or to replicate a setup. The flexibility of qmrestore is particularly notable, allowing for restoration on original or specific storages, overwriting existing machines, or restoring in the background while starting the VM.

Use case 1: Restore virtual machine from given backup file on the original storage

Code:

qmrestore path/to/vzdump-qemu-100.vma.lzo 100

Motivation:

This command is commonly used when a virtual machine needs to be reestablished exactly as it was at the time of backup. This might be needed after errors, accidental deletions, or corruption occurs in the current running instance. By restoring from the backup file, administrators ensure that the virtual machine is reverted to a stable state.

Explanation:

• path/to/vzdump-qemu-100.vma.lzo: This specifies the path to the backup file that contains the virtual machine’s data. The file format shows that it’s compressed with lzo to save space.

• 100: This is the VMID, a unique identifier for the virtual machine within Proxmox. The command will restore the backup to this VMID so that it maps directly to the existing virtual machine configuration.

Example Output:

Restoring VM 100 from backup path/to/vzdump-qemu-100.vma.lzo...
100% complete. VM 100 restored successfully.

Use case 2: Overwrite existing virtual machine from a given backup file on the original storage

Code:

qmrestore path/to/vzdump-qemu-100.vma.lzo 100 --force true

Motivation:

This command is essential when an administrator needs to replace the current state of a virtual machine with a backup, regardless of its current condition. This is particularly critical during disaster recovery operations when existing VM states are compromised and must be supplanted by backed-up versions.

Explanation:

• path/to/vzdump-qemu-100.vma.lzo: Indicates the location and name of the backup file to be used.

• 100: Refers to the VMID of the virtual machine to be overwritten with the backup content.

• --force true: This option explicitly allows the backup to overwrite the existing contents of the VMID, ensuring that the restoration occurs even if the system detects an existing set of configurations.

Example Output:

Existing VM 100 detected. 
Forcing overwrite...
100% complete. VM 100 restored and overwritten successfully.

Use case 3: Restore the virtual machine from a given backup file on specific storage

Code:

qmrestore path/to/vzdump-qemu-100.vma.lzo 100 --storage local

Motivation:

Utilizing specific storage for restoration can be crucial for managing available resources and optimizing storage usage across a Proxmox infrastructure. By directing the restore operation to specific storage, administrators can allocate the restore location according to current resource utilization and necessary proximity for performance considerations.

Explanation:

• path/to/vzdump-qemu-100.vma.lzo: Directs to the backup file required for restore.

• 100: Serves as the identifier for the virtual machine to be restored.

• --storage local: Specifies the target storage where the VM will be restored. This can be particularly useful when dealing with multiple storage setups and needing control over where to deploy the virtual machine.

Example Output:

Restoring VM 100 from backup path/to/vzdump-qemu-100.vma.lzo to storage 'local'...
Storage found. Deploying on specified storage.
100% complete. VM 100 restored on 'local' storage successfully.

Use case 4: Start virtual machine immediately from the backup while restoring in the background (only on Proxmox Backup Server)

Code:

qmrestore path/to/vzdump-qemu-100.vma.lzo 100 --live-restore true

Motivation:

The live restore feature is particularly advantageous in scenarios where minimizing downtime is crucial. This capability allows users to start the virtual machine operation concurrently while restoration processes are executed in the background. In environments such as critical application servers or database servers, this facility can prevent loss of access or service provision during restorations.

Explanation:

• path/to/vzdump-qemu-100.vma.lzo: Points to the backup file to be restored.

• 100: Indicates the VMID for the restoration.

• --live-restore true: Enables the live restore functionality, allowing the virtual machine to start immediately, with the full restoration process completing in the background.

Example Output:

Initiating live restoration for VM 100 from path/to/vzdump-qemu-100.vma.lzo...
VM 100 started. Background restoration in progress.
75% complete in background. VM operational.

Conclusion:

The qmrestore command proves to be an essential tool in ensuring the resilience and flexibility of virtual machine environments managed by Proxmox. Each use case provided demonstrates scenarios where this command can effectively meet the needs of systems administrators, from simply restoring prior states to complex real-time operational continuity. Through its variety of options, qmrestore aligns with best practices for proactive management and disaster recovery in virtualized environments.