The qm snapshot command is a command-line tool provided by the QEMU/KVM Virtual Machine Manager that allows users to create a snapshot of a running virtual machine. A snapshot is a point-in-time copy of a virtual machine’s state, including its disks, memory, and CPU state. Snapshots are useful for creating backups of virtual machines, testing new software or configurations, and rolling back changes made to a virtual machine.
To use qm snapshot, users need to specify the ID number of the virtual machine they want to snapshot and a name for the snapshot.
qm snapshot Command Examples
1. Create a snapshot of a specific virtual machine:
# qm snapshot {{vm_id}} {{snapshot_name}}
2. Create a snapshot with a specific description:
# qm snapshot {{vm_id}} {{snapshot_name}} --description{{description}}
3. Create a snapshot including the vmstate:
# qm snapshot {{vm_id}} {{snapshot_name}} --description{{description}} --vmstate 1
Summary
Once the qm snapshot command is executed, the virtual machine’s state is frozen, and a new snapshot is created. Users can then use other commands in the QEMU/KVM Virtual Machine Manager to manage the virtual machine and its snapshots, including restoring, deleting, and rolling back to previous snapshots.
One important thing to note is that snapshots can consume a significant amount of disk space, especially if they are kept for an extended period of time or if the virtual machine has a large amount of data. Users should be careful to monitor disk space usage and regularly delete old or unnecessary snapshots to avoid running out of disk space.
In addition to qm snapshot, the QEMU/KVM Virtual Machine Manager provides a variety of other commands and features for managing virtual machines and their snapshots. More information about qm snapshot and other features of the QEMU/KVM Virtual Machine Manager can be found in the project’s documentation at https://pve.proxmox.com/pve-docs/qm.1.html.