You can suspend a VM to disk with the GUI option Hibernate or with
qm suspend ID --todisk
That means that the current content of the memory will be saved onto disk and the VM gets stopped. On the next start, the memory content will be loaded and the VM can continue where it was left off.
State storage selection
If no target storage for the memory is given, it will be automatically chosen, the first of:
- The storage vmstatestorage from the VM config.
- The first shared storage from any VM disk.
- The first non-shared storage from any VM disk.
- The storage local as a fallback.